Building Combat Encounters

This is posting eight and a half hours early because somebody is whiner and wanted something to read while he was at work.

Just a forewarning, this one is a lengthy one. It took me over a week to complete and there are parts where it kind of bounces all over the place. Hope it is useful to someone.

Building encounters is a tricky thing in DnD. Every edition has rules and guidelines for doing so based on an assigned value to players and their level and an assigned value for the difficulty of monsters and NPCs. These rules have in my experience always been a bit off. They don't really account for things like min/maxers or unique features of your campaign (which admittedly makes sense) or even having an imbalanced party (one that isn't made up of varied character types like the classic Cleric, Fighter, Rogue, Wizard setup). As an example, guns in Pathfinder completely negate the majority of the difficulty in combat encounters in a faux-medieval society because they're treated as touch attacks and touch attacks don't factor in armor bonuses to AC. My point is that there's always a bit of fiddling you have to do as the GM. Which is ok. That's what GMs do. We fiddle with bits and pieces of rules and stories till something develops and everybody has a good time and players shit all over everything you've built. I'm not going to give concrete numerical advice on challenge ratings and tweaking them. You as the DM are going to have to base that on your players. You're going to have think critically about it. A group that relies on direct weapon damage is going to have more trouble fighting foes resistant to weapon damage than a group with lots of spell support. A group without a caster capable of healing is going to have more trouble recovering from fights and staying in fighting shape during fights, than a more balanced group. A group with fairly low Wisdom scores is going to have more trouble facing off against enchantment magic or creature with mental attacks. A group of heavily armored, low Dexterity characters is going to have more trouble facing foes that utilize breath weapons and area of effect spells/effects. You're going to need to be aware of what your party can do and how they fight to know how their strengths and weaknesses are going to impact the difficulty of an encounter you plant to have them go through.

Encounter building is tricky business, as I said. You want to challenge your players, but you also want to let them shine. You also want them to experience awesome moments. But if everything is an awesome moment where they are winning at combat all the time and doing amazeballs things, it's not challenging and it's boring. So that's the line you have to walk. You have to challenge them without resorting to negating their capabilities, while also keeping them engaged while making sure combat isn't a boring as fuck slog of trading blows until someone runs out of hit points. So that's what this post is about. We're going to talk about 1) keeping players engaged, 2) making encounters challenging without just negating everything about a group's strengths, 3) letting player's be cool, and 4) keeping things from being too boring. Keeping players engaged and keeping things from being boring are separate points here because players disengaging from the encounter isn't always because they're bored.

1) Keeping Players Engaged During Combat

The quickest and dirtiest way to keep players engaged is to hurt their characters. Nobody is as laser focused on what's going on as they are when their character is in the middle of combat and has three hit points left and is surrounded by foes. There is a caveat to that though. They need to give a shit about their character. So that's the real way you keep players engaged during combat: they need to be invested in the outcome of the combat. This can mean they really care about progressing the plot (assuming the combat is related to the plot) or that they really care about their character. I really really like Navere, but I give no fucks about defeating Strahd. So yeah, I'm invested when we're defeating Druids that serve Strahd, but not because we're taking apart a component of Strahd's regime, it's because I don't want Navere to die and because he hates those fucking dumbfuck Druids.

To keep players engaged during a combat encounter, you need to make them care about some aspect of the outcome of the combat. That will keep the minds of the players in the on position. We want their minds in the on position analyzing the combat and thinking about the outcome and what could happen and what the ramifications of success and failure are for their characters, the party, and the campaign. If the ramifications for those three things are "meh" in their minds, then they're going to play with their phone and not be prepared when their turn comes up and not care when anything happens. Our goal is to have them care, to have them be invested and care about all of the things.

Another way of keeping players engaged is describing things as they happen. As the DM, players tend to pay attention when you start talking at length. If you're describing things as they happen in combat, it is going to eat up time, but your players are going to naturally pay attention to you and what is going on a little bit more because despite all their many flaws, players in the middle of a session do tend to quiet down and listen a little bit more if the DM is talking and saying more than "he moves here" or "you hit" or "he misses."

Ultimately, keeping players engaged is something the DM has to figure out for himself. You have to know your group and what type of players they are and base it on that. Some people really like combat and will naturally pay attention more during it. Some people are going to be paying attention because the combat is related to a character or plot element they care about. Others are only really going to pay attention if their character is close to dropping. Some people are only going to be engaged during combat when they're doing well at it. Some people just aren't going to be engaged during combats because they don't care about them and it's not what interests them. Different players are going to be engaged by different elements of the game. You as the DM need to figure out how to draw them in and that's something you can only really do by paying attention to your players during sessions or by asking them directly. Which I recommend. If someone is perpetually not engaged during a combat, ask them why. 

2) Making Encounters Challenging Without Negating Everything About a Group's Strengths

Let me start this section out by saying that there are definitely times where it is ok to deliberately and with malice aforethought negate a party's strengths.

If a foe is a certain way and the plot/player choices force you to create an encounter where the PCs are facing that foe, you make the foe the way it is. If the party is composed of fire focused Sorcerers and they decide to seek out and slay a gold or red dragon because real good super awesome reasons, the dragon is what it is and it is immune to fire. Is it "fair" to the players? Is it "balanced" for the party? Not really. They have a narrowly focused group and the creature negates the majority of their combat ability. But so what? They chose to do a stupid thing. Sorry guys, you did this to yourself. I'm sorry your choices led you into an unfair fight, and I have no idea how you'll survive this fight, but consider not being fuckheads next time. That might help. In Orcunraytrel, the PCs ended up being pitted against the Nel, who have a host of immunities and resistances like immunity to critical hits, regeneration, elemental resistances, and immense supernatural might. They weren't fair and they weren't balanced and there were times when the players had a rough time dealing with them, but the progression of the plot dictated that the players needed to face them. So that's what happened. Despite the deck being stacked slightly against them, they overcame the Nel. Multiple times. These fuckhead deserter pirate lords fought and defeated multiple immortal supernatural creatures. They got their shit together, learned about their foes, and did awesome violent things to them. 

To continue, if a foe has seen the PCs fight before and knows they're coming for him or seeks their downfall, you are completely justified in negating some or all of the party's strengths. This also holds true for foes with access to divination spells and diviners and that sort of thing. As long as an enemy is aware the PCs are after them and has time and resources necessary to do so, they're justified in knowing at least some of the capabilities of the PCs and making an effort at protecting themselves from those capabilities. Unless they're are morons. Morons typically don't exhibit that sort of forethought. 

As a prime example of  NPCs/BBEGs working to negate a party's capabilities, let's look at Strahd. Strahd has directly encountered Navere and his friends twice now and has countless spies in Barovia. He knows at least some of our moves. Strahd is also a several centuries old lord of a region and is a lord who likely collects taxes of some kind (or collected them at one time) and also has likely faced many an adventurer. Basically what I'm saying is that Strahd has infinite time and resources and therefore has theoretical access to any and all magic items in the DMG. If he decides we pose a threat and we decide to go after him, he is perfectly justified in wandering down to his basement and finding magic items that negate some or all of our capabilities. Is this fair to us? Not really, because it gives an already tough encounter additional advantages beyond the scope of Strahd's CR, whatever that might be. But it makes sense because Strahd is an intelligent foe with a masterful command of tactics and has infinite resources and countless spies. He's not going to face off against our werebear Witcher and say, "Oh fiddlesticks! If only I had decided to wear gloves and use a silver sword today!" He's going to find a fancy set of gloves that allow him a good grip while creating a barrier between his hands and the hilt of the silver sword (which should be made of like wood and leather and not a problem in the first place, but whatever) and then find the sword carried by a dead adventurer and use it to give the werebear Witcher a hard time.

So those are two types of situations where we are allowed to negate some or all the strengths of a party. I'm sure there are plenty more. Let's move on though. How do we make combat challenging without resorting to straight up negating a party's abilities?

Don't fudge numbers in the party's favor. This is just an idea and I don't follow it because I'm very much in favor of fudging numbers on both sides for the sake of excitement and tension and making players feel cool. That said, it is a valid way of making combat a wee bit more challenging. Kind of.

Make fewer fights during sessions and make the fights that you do plan more difficult. This is something I do in most of my campaigns. This increases the likelihood that your players and their characters are at peak fighting power, and therefore they can face off against what the DMG classifies as hard or deadly encounters with less likelihood of PCs dying or wiping the party. If your plot related combats are continually just a hair more difficult than the party should really be facing, but aren't resulting in constant player death, the players are going to learn that combat is tough and brutal and is not something that they can really afford to just half ass it through. Over time it is going to sort of bake in a certain amount of tension. Ideally. If players start learning that every combat is a close one, they're going to realize that they have to stay engaged because every fight is challenging and runs the risk of player death if they phone it in. This is a risky game to play with combat though, because if you're not on your toes as the DM, you're going to TPK your players. If you're going to go with this route of manufacturing challenge and tension, you have to know the game to your bones and understand the way the math works. It also means that when the players face a boss, you have to make the bosses a step above what are already challenging encounters to ensure that the progression of fights makes sense in terms of escalating difficulty. So once again, you're walking the knife's edge. This route can manufacture tension and challenge, but it also has the added benefit of teaching players to be cautious. If your players evolve and adapt to this campaign of very close combats they're going to be more cautious about combats. They're going to seek advantages before closing in on bosses. If the players respond this way to a campaign containing such combats, then boss fights that are more deadly aren't going to be quite as risky to run. Maybe. It depends on your players and what the plot dictates that they fight.

Tactics. I say this a lot. Use tactics befitting a foe's intelligence and nature to impact the challenge of an encounter. Intelligent foes do intelligent things. Stupid foes do stupid things. Berserkers in a blood rage are going to keep fucking attacking even if their intestines are spooling out of their guts and tangling up their feet. Golems instructed to slug the closest thing are going to keep slugging the closest thing until it's not a close thing, even if that thing is immune to slugging. Hungry animals are going to attack until they're heavily wounded or until they die if they're defending a nest or their young. Honor bound veteran soldiers defending their borders are going to use choke points and their knowledge of the terrain to their advantage, and they're going to fight to the death to protect what they value. Green troops are probably going to be easily intimidated into laying down arms after a few of their companions fall, or they'll outright flee. Terrorists and zealots are going to take out as many foes as they can, however they can, regardless of the cost to themselves. Mercenaries and assassins are going to flee when they start to lose, and perhaps come back another day if their contract or their butthurt warrants it, and this time they'll know what the PCs are capable of. Politicians and nobility are going to use the full weight of their position in society to impede the PCs well before initiative checks, and after the fight there are likely to be legal consequences for the PCs regardless of the outcome of the combat. Wizards in their towers are going to protect their homes with glyphs of whatever, magical constructs, and spells like guards and wards. Commanders that see a group of foes surviving wave after wave of soldiers because of a healer in the back are going to direct archers to fire on that healer. That same commander is going to use mobile rapid attack units to kite slow moving heavily armored enemies. Goblins are going to use stealth and surprise and overwhelming numbers and are going to run away and come back with more stealth and surprise and larger numbers if they start to take heavy casualties. Intelligent supernatural creatures that are resistant to the non-magical weapons of Fighters are going to ignore the Fighters that are giving them papercuts and take out the magic users that can actually hurt them first. Foes that see a heavily wounded PC are going to concentrate fire just like players do when they see a heavily wounded enemy. If the PCs are in the home of whoever they're fighting, like a cave system of goblins or lizardmen, their foes aren't going to flee the place completely if they find that they're outmatched by the PCs. This is their home. They have family and friends here (if you're one of those people that believes "evil" can't have friends or strong emotional bonds, you do not understand the complexities of humanoid psychology and morality). They're going to flee one encounter, find more of their people, and rally to defend their home and increase the number of foes the PCs face in a later encounter and warn their friends and family about the fucking pointed hat wearing motherfucker in back that threw a ball of fire that incinerated Jimbo, Cooter, and Billy. Strahd knows we have weapons and that they don't really hurt him and he regenerates the damage anyways, but he also knows that we have a Monk with radiant damage laser fists and a smitey Paladin, and a radiant damage moonbeaming Druid. Strahd certainly does not think in game terms like radiant damage vs. non-magical weapon damage and regenerating 10 hit points a round. However, he definitely thinks steel is amusing because he heals quickly from its injuries and he knows the white flames of our laser fists and moonbeams really fucking hurts and keeps him from regenerating. So he's going to ignore the adorable Witcher and his itty bitty steel axe, and he's going to eat the faces off of the bright white holy fire users in the party. Because they're the threat and once they're gone he can toy with the lumberjack monster hunter to his heart's content.

Another way to create challenging encounters is to factor in the environment. There were actually rules for this in Pathfinder. If the terrain was particularly favorable to the enemies, you were supposed to increase the CR of the encounter by one. In general terms, this can be as easy as plopping down Gears of War style waist high cover between the PCs and their foes, assuming that sort of thing is sensible for the terrain to have. Or stretches of difficult terrain. If we're talking about ancient tombs and treasure rooms with guardians, throw down a few traps as well. This creates a good amount of tension because now the PCs have to fight their foes and worry about where they step next. It also potentially pulls a PC off of combat duty into finding and disarming traps duty. If we want to get real dramatic we can do things like I talked about in my dragons are boring in 5th Edition post from several weeks back. You can set up situations where fiery creatures have volcanic vents and lava flows in their lair. Are the players investigating the tomb of ancient necromancers? Well, maybe the area is so rife with necrotic energy that healing spells are impeded or the aura of energy is so strong it poisons the characters or deals direct damage every hour spent in the area. Intelligent foes are going to surround themselves with an environment that benefits them. It's why humans do things like build walls and bridges. A Wizard or Sorcerer that focuses on water magic is going to surround himself with water. If such a guy has magic or an item that grants him the ability to breathe underwater, why would he live out of the water? Well, spellbooks, but whatever. You get what I mean. Think about your creatures. Don't just look at the stats. Well, look at the stats and abilities yes, but don't get blinders. Where would this creature choose to live? Why? Why would a goblin live in a cave system with convenient 10 foot wide and 10 foot tall hallways when it is only three feet tall? Combat done single file while on your hands and knees is going to be significantly more difficult, even if you're just facing off against one goblin at a time in front of you, nevermind how bad things are going to get when more goblins come up behind you and you're defending yourself with your butt cheeks and boot soles.

Modifying existing monsters is another way you can challenge players. It works on two levels, it makes monsters more difficult to face off against (most of the time) and it destroys the preconceived notions of experienced players. For instance, you have an iron golem. Big bad iron bruisers that hit things and occasionally breathe poison clouds. They're fairly well known and understood and even if we don't know their exact stats, we can extrapolate some of them based on its description. What if the Wizard that created a particular iron golem used a wand of lightning bolts or some similar item in the creation of the golem and now every time the golem's fist connects with a player they get hit by big iron fists and a shocking grasp spell? Or maybe the Wizard animated the golem with a lightning elemental inside of it. That sounds like a lot of fun. What if a clan of goblins has taken lessons (or beatings) from their hobgoblin cousins and have become obsessed with order and martial might? Now they have the morale necessary to stand and fight and the tactical knowledge to understand things like shield walls and concentrating ranged fire. What if another clan of goblins practices the Way of Shadows monastic tradition because they understand that they are scrawny little fucks and stealth and trickery are the keys to their survival? What if Strahd trains and breeds rust monsters in his free time and has a herd of them that have been bred to go bugnuts crazy over silver? He's also obviously had his dumbfuck redneck druids cast barkskin on the rust monsters as well. What if owlbears were created from owls and cave bears instead of regular bears? What if the werewolf is a winter werewolf? What if the metallic looking blue dragon is the child of a gold and blue dragon and he breathes beams of fucking lightning fire?

This particular option is the easiest way to create challenging encounters and make them a little more interesting. If you can create a complex character with a variety of strengths and weaknesses from a combination of race, class, archetype, feat, and skill selection, you can create an interesting enemy for players to face that is a variation on a pre-existing one. That reminds me. Add class levels to pre-existing enemies. Why should the goblin king just be a regular goblin with max hit points? Leave his base stats as is, but give him two levels of Rogue and everything that entails. Are the players hunting a mythical wolf that lives in a mythical forest with strong links to the Feywild? Make it intelligent and give it levels of Ranger or even Druid. Are the players hunting a rabid beast that has been preying on townsfolk and livestock? Give it Barbarian levels. You don't even necessarily need to give full levels in these situations, just flavor the creatures with class abilities.

There's one thing you need to keep in mind when altering pre-existing creatures. How do these creatures affect the rest of your world? If we're talking about the child of a blue and gold dragon, can all dragons interbreed? Why? Because magic is an acceptable answer here. If all dragons can't interbreed, was this just a special case of Bahamut and Tiamat bestowing their favor on the pair? Why did they do so? Will they be pissed if this special child of dragonkind is murdered by greedy little monkeys? If the golem has a lightning wand used in its creation and has shocky powers because of it, are all golems modifiable in this sort of way? Or was the creator just that good at golem creation? Did he write his methods down? Are they valuable to other spellcasters? If the PCs possess this info, will others try to take it from them? If goblins can adhere to a monastic tradition, what other monstrous races can? Are there tribes of Wizard goblins too? There aren't. Goblins think written words are magic and are scared of them.

My point is, just be aware that when you make something exist in your world, you're making it exist in your world. Take a few minutes to think about how this affects the rest of the world. In most cases, it doesn't do too much. But in a case where you go on and on and on about how there are no additional planes in your universe beyond the prime material (or whatever you want to call it), but you have a clan of Way of Shadow/Shadowdancer goblins, it may raise some questions in the minds of your players. How can the goblins jump through shadows if there is no Plane of Shadow to jump through? How can these goblins do things with shadowstuff if the place shadowstuff comes from, the Plane of Shadows, doesn't exist?

4) Keeping Things From Getting Too Boring

Fights get boring. It happens. The DM cannot be expected to make every single moment of combat in a campaign be like an action sequence out of John Wick. That said, there are things you can do to minimize boredom during encounters.

The first step to keeping things from being boring is to remove boring shit. So, remove random encounters. Unless you're talking about special encounters where there is a small chance that important NPC/creature/item X will be at location Y. Don't waste your time and the time of your players on the party coming across six bandits in the woods. Hmm. Rather than calling this idea removing random encounters, let me change it up. How about we go with remove innately boring encounters from your game. Seasoned adventurers can be hot shit and it is assumed that even as rookies they are a least slightly competent at keeping their insides inside of them. Don't waste their time fighting bucktoothed back woods bandits or unarmored street thugs with metal pipes. If such a situation arises, don't waste half an hour or an hour on it. Either handwave the encounter and describe how the PCs cut through these faceless mooks or charge them hit points or a hit dice or something to indicate that they expended effort or something. This doesn't mean they walk through all bandits or thugs. Because sometimes NPCs can be hot shit too. If every time during a campaign you've handwaved the PCs cutting their way through random thugs and all of sudden they're rolling initiative when facing off against some supposedly random thugs, they're going to wonder what is up and they're going to be engaged and they're going to be interested. Maybe. However, that can work against you. The players may decide this break with tradition means that a scorched earth policy is best and blow a bunch of once per day abilities before they even know what they're really dealing with. So your extra special bandits led by Kazandor, The Black Smile of the Night all eat a fireball immediately followed by a flamestrike and you don't get to do anything with Kazandor and his shadowdancing bandits. There are pros and cons to doing things this way.

If you end up in a situation where a particular combat is taaaakkkkkiiiiiinnnnngggg forever. Call the fights that are already won. If the players have used a bunch of cool abilities and the foes are still kicking and the fight is turning into a slog with both sides spamming attacks and cantrips just wasting time till the NPCs run out of hit points, just call it. If you know the PCs are going to win and you don't have anything planned to upset the dynamic of the battle, just call it. Charge the players a few hit points or hit dice or a spell slot (or don't) and describe them slaying all their foes. This will cut down significantly on how much time the fight eats up and keep boredom levels from reaching critical mass. It will keep things moving and lead to less overall boredom during the session.

Don't call the fight if the enemy is a boss or BBEG. If the players and characters have been seeking this shmuck's downfall for a while, don't take that away from them with your magical DM words. Even if the fight is turning into a slog, it's my opinion that they need to strike that last blow in real time and not hear you describe it to them.

Make the environments of a combat interactive. Don't build your encounters in such a way that your players feel like their only options are to trade blows with enemies in a featureless grey room. If they feel that way, the combat is boring. Firstly, describe your environments thoroughly. What do they look like? Smell like? Feel like? ...Taste like? What's the temperature like? What's the lighting like? Make the players feel like their PCs are in an environment. Then make things for them to interact with (assuming that sort of thing fits with the environment). Are there braziers full of burning coals? Is there a table they can kick over for cover against a knife chucking thief in the corner? Is the support beam weak enough that a thunderwave or Monk's attack could bring down the room on the top of the heads of the player's foes? Are things flammable? There are two parts to this. The first is that the players have to be interested in interacting with the environment during a combat. The second part is that you as the DM have to have a history of making the environment offer things to interact with and your players need to know that doing so is not going to be a complete waste of their turn/time.

There has to be value in interacting with the environment. Otherwise there's no point in doing so and it's more valuable for the players to keep attacking. This doesn't mean that a kicked over brazier should be the equivalent of a fireball. But it should do something that makes it worth doing. You could make the case that if your players want to do something they think might be cool, they should do it without worrying about a cost/benefit analysis of the action vs. making a regular attack, but DnD is still a game so the actions you take instead of leveraging more conventional damage against your foes should have some degree of value to the ongoing combat. If you waste your turn kicking over a brazier of burning coals instead of doing an attack and the coals only do 1d4 fire damage once, you've wasted your turn and put yourself and your party members at risk by prolonging the fight. Which isn't cool in a cooperative game like this. Like I said, it doesn't need to be the equivalent of a fireball or something, but if the players are going to interact with the environment, it should have value. But only if the thing they do warrants it. You could make a case for a brazier of coals covering a wide area and doing 1d6 fire damage when anyone is in the area and lighting things on fire and even being considered difficult terrain. But a player that decided to throw a lit candle at someone probably shouldn't get the same effect. Because it's just a candle. Sometimes players are going to want to do cool things and think creatively about how to do so, so try and reward that. Other times they're going to want to do something stupid without thinking about it, don't reward that.

Don't make players fight the same enemies in the same situations over and over and over again. Yeah, you may be on a quest line that pits the players against goblins for several scenarios, but as previously said, you can make goblins interesting by changing them up a little. If the players fight the same enemies in the same types of situations over and over and over again, combat is going to start to bore them. As long as the situation allows it, you can change things up even if the quest line forces them to be fighting against the same type of foe for several scenarios. In a goblin cave complex that will take several sessions to get through, even in a situation where you're not making them unique Way of Shadows Monk goblins, you can vary things a bit. Throw in a hoblgoblin or bugbear or two. Throw in an otyugh or ooze or something in a midden heap. Make a few goblins acolytes of Maglubiyet and give them Cleric spells. Change up the types of encounters. Don't just put a set of foes on one side of a room and the PCs on the other. Pit the players against ambushers, archers, front line warriors. Put them in hostage situations where the goal of the combat is not to defeat the foes, but to save the hostages. One of the key things to keeping combat interesting is variety. Doing the same type of thing to the same type of NPCs for an entire campaign is almost the definition of boring. You want variety in the foes your players face and in the types of combat situations you put them in.

4.X) Challenging Specific Types of Players

This is something I forgot to mention at the beginning of the post. You may want to challenge specific types of players in some way. The thing to keep in mind is the difference between challenging the player and their character and negating their abilities. Negating is keeping them from using their most powerful abilities (cutting an archer's bowstring, forcing a Wizard into direct combat against an enemy that is immune to magic, forcing a Fighter into combat with a creature immune to weapon damage, etc). Challenging them is forcing them to use those abilities in a difficult situation or at a higher level of expertise than they are accustomed to.

So yeah, if you want to negate a PCs abilities, go ahead. Cut bowstrings. Wizard falls in lava, burn his spellbook. Fighting goblins (who fear words and love shiny things)? Have them steal holy symbols and spellbooks. Is your Fighter hacking apart a demon lord or vampire and is only able to do so because of the magic sword he wields? Have the demon lord or vampire use its superior Strength score to use some sort of opposed check to grab the sword and chuck it into a corner. Intelligent creatures understand when they are being injured and they would seek to avoid that. Is the Paladin basically invulnerable because of his plate mail and shield? Have an enemy bury a heavy spear in the shield and force him to drop it or reduce the shield's effective. There are lots of reasonable ways you can temporarily negate a PCs capabilities to challenge them. Just don't do it all the time or do it just because you're sick of the PCs kicking your NPCs all over the place. Because that's a dick move and it makes you a babby. I'm not gonna lie, we've all done it. We've all been there. Do your best to avoid it though. It leaves a bad taste in everyone's mouth.

Also, remember, if you can have your regular old NPCs (not the special unique boss types with special abilities) do something, the players can have their character's do it too. Keep that in mind when you decide on what mechanic you use to determine if a spear sticks in a shield or an enemy is able to disarm a PC. Similar to what I said earlier about adding things to your world, when you add a mechanic to your world, you add it to your world and it becomes available for everyone to use. So make sure you've thought about the mechanics you want to add. Also, make sure you're not stepping on existing capabilities of classes and stuff. If a class has a specific ability that allows it to disarm foes (I think one of the Fighter archetypes does) make sure your disarming mechanic isn't as cool as that. 

Challenging specific types of players is different. Pathfinder had a broken condition for items that had specific effects on gear types. You can use a similar mechanic to make things harder for gear based characters. A fireball hits your archer and he fails his save? Scorch his bowstring. Until he replaces or repairs it, his bow attacks have disadvantage because of the damaged string. Your Fighter use his greatsword as a lever to move a rock because he didn't bring a crowbar to the dungeon (dumbass)? Ok, let him succeed, but until he can find a forge or use a smithing hammer to repair the greatsword, his attacks with the slightly bent and blunted weapon have disadvantage. Your Wizard fall into a lake? Now the ink on his spellbook is smudged and runny, so when he tries to cast rituals from it they take thirty minutes instead of ten because he has to decipher the smudges. Did your Cleric get covered in a slimy ooze creature? Ok, well creatures have advantage on saves against his spells because Sune, the Goddess of Beauty is upset that the Cleric and his holy symbol are dirty and covered in gross ooze bits.

These are inconveniences that make it difficult for characters and players to do what they like doing. Be careful though. Players like playing a certain way because they enjoy it. If the DM is constantly throwing up roadblocks that prevent them from doing those sorts of things, the game ceases to be fun because they can't play their character the way they want to. You probably don't want to do these sorts of things all the time in most campaigns. However, if you're going to run a campaign where leather armor and paper and bowstrings are constantly being damaged by area of effect fire spells or when the player is lit on fire, you need to make your players aware that that element of realism is a component of your campaign before the campaign begins, and you need to be consistent about doing so. Don't be the DM that decides on this sort of thing when you're in the middle of the campaign and the Wizard tries to cast a ritual that ruins a puzzle trap you've put into the scenario and you say "Oh, well, you were inside a gelatinous ooze for a while and its acidic body damaged all your clothing and your spell component pouch so you can't cast that ritual. Sorry." That's crap DMing. 

Like I said, broken weapons, lost spellbooks, ruined armor, etc, are all inconveniences to players that prevent them from doing what they're good at or make it harder to do what they're good at. The other way of challenging specific types of players is to require their level of expertise. They have to do things that only they are good at. If you have an archer character that is ridiculously good at ranged attacks, use that. Make a trap or monster that requires that level of expertise to get past. Give giant mechanical monsters weak points with an AC that only your badass archer could conceivably hit to damage the right gear and reduce the monster's mobility or break off a layer of its armor plating so the Fighter can start banging away on its sensitive internal components. Put PCs in a situation where only the fire focused Sorcerer has the ability to cast a fireball that deals enough fire damage to ignite The Shrine of the Fire Lord's Favor. Put in trapped hallways where only your Rogue has a high enough Dexterity save to reliably survive all the traps in the trapped tunnel to get to the lever they need to raise the portcullis in room A1. Put your party in a situation where they are mobbed by so many mindless undead that no matter how many the Ranger and Fighter kill, there are always more, so the only party member that can give them enough breathing room to advance is the Cleric with his turn undead ability. Basically, create environments and situations and monsters that require the level of expertise your players have developed in their playstyles and character design and then fold all that together into a scenario. This sort of thing can be tricky to do and has its flaws (what if they use the wrong ability at the wrong time in the scenario, what if the needed player isn't there that night, etc), but if done right it gives each of your players moments to shine where they are doing what they want to do and doing it well. It will also serve as a team building exercise where they're all learning to depend on one another's capabilities. 

3) Letting Players Be Cool

I wanted to end on this one rather than keeping things from getting too boring. I'm not sure why. It felt right. I went with it.

This first idea is kind of an odd idea I just came up with. You have a variety of players with a lot of different skills and some overlap between the PCs. You might have a Rogue proficient in Dexterity saving throws and a high Dexterity Monk that isn't (maybe, I forget what saving throws Monks are proficient in). They might both be called on to do Dexterity save related things. The idea I have is to describe the proficient character's high score successes as being skill based and intentional and deliberate and the non-proficient character's successes as being accidental or reactionary. I'll give an example. So you have this Rogue and Monk moving down this tunnel with a floor full of a bunch of trapped tiles. Both PCs trip pressure plates while moving in the tunnel. They both make Dexterity saves and roll super high. The Rogue is proficient in things like Dexterity saves and Stealth and thieves' tools and such and has a mediocre roll. The Monk just has a high Dexterity and a really high roll. They both succeed on the saving throw. Describe the Rogue as feeling the slight give of the pressure plate, balancing his weight carefully and sliding his boots to be half on one tile and half on an adjacent one. He avoids the trap by carefully distributing his weight across multiple tiles so none of them activate the trap. The Monk just goes "Oh fuck" and does flippy ninja shit to get out of the way of the trap's effect. The Rogue could do flippy ninja dodge shit too, but describing it this way shows he's good at what he does. He doesn't need to be lucky or do ridiculous looking flippy ninja shit to dodge a dart or firebolt, he just calmly and skillfully avoids tripping the trap in the first place while the amateur runs around making a spectacle. If your player thinks flippy ninja shit is way cooler than being really good at Rogueing, this option probably isn't going to go over well. So know your players and use that information to determine what they'll think is cool.

Second thing. Let your players surprise you. One of the super neat things about being a player is when you surprise the GM. You've seen the memes. That moment when you make the DM say fuuuuucccckkk. I've said things about knowing the capabilities of your players in this post. What I mean by that is know them in a general sense. How do they fight? Can they heal? Do they like fire? Those sorts of things. But don't know the nitty gritty details of their character sheets. What are their specific stats? Don't worry about it. Do they know fireball or firebolt? Don't worry about it. What archetype are they? Meh. Let them have that badass moment where they use an ability or spell you had no idea they had to negate six paragraphs of your scenario or campaign documentation because they have etherealwhatever and can just ghost through the walls of the dungeon instead of being forced to answer the riddles of Mokmhet the Stone Ancient of Broken Dreams and Weariness and the Aching Pangs of Loneliness. It's cool. Let them do that. 

Third thing. Try not to ask them "Are you sure?" too regularly because that is DM speak for "you're about to get fuuuuuucccckkked" and players know that. Unless you've deliberately sidestepped that expectation by always asking them if they're sure  about their next action even when it doesn't matter, so they have no idea what you mean when you ask them if they're sure. My point here is honor their choices. It may not be cool when they pick up the ancient iron rune encrusted battle axe that emits malevolent whispers and they get possessed by Garobgul, the Blade Whispering Against the Throat of Time. Well. That's not true. It's going to be super cool because I'm a pretty decent writer and I describe things pretty well.

Moving along. It may not be cool for the player that picks it up when he picks it up. However, a year later when the group is in the final session of the campaign and they've fought through the hordes of death and at least three of the layers of Hell to reach their former companion and have chained them to the Altar of Ambivalent Servitude and the possessed PC is allowed to make a Wisdom save to throw off the mental chains of Garobgul and succeeds by one and I describe a really awesome mental struggle and beams of light and darkness and a whisper of pain and rage that grinds like a knife against your eardrums, that's gonna be cool.

That was a helluva run on sentence. 

Ok, fine. I admit it. There are definitely some flaws with that situation that make it not cool. My point is, yeah, it sucks when players make bad choices, but don't warn them with words you speak as the DM and take away a sliver of their ability to make decisions. When you speak to them as a DM like that you're implying they're making the wrong choice and you're eating away at their commitment to a course of action. They've already decided to do something and you are gnawing away at that. Sure, throw up flags in the world like a crusty old war veteran that warns them about the fell darkness and horrible voices he heard when he fought against the vampire counts on The Fields of Red Ruin in the Westlands. That's completely different from you saying, "Are you sure?" with the tone and cadence you always do when you are warning them that bad shit is about to go down. Give them as much practical in world information and warning as you reasonably can, and then let them make their shitty choices and get knocked down, then let them get back up and hit back twice as hard. Because that's cool. They're PCs. They don't give up. They don't tap out. They drink as a Dogdamn move action, first produce their pistol, then produce their rapier, and they fucking stand and fucking deliver.

They fuck up and they fall, but much like Hercules Mulligan, they get the fuck back up again. ::wink:: Give them the chance to fail, so they know that they can. If they know that they can fail, their victories and successes are that much more valuable. I have seen many a PC wander around the game world not really cognizant of the fact that they can fail and lose and have their PC die with no restoration possible. The player knows he's playing a game and why would the main characters die forever? His victories don't matter because that's the expectation, that he'll be victorious. Let the players understand that they can fail and make the wrong choice, that it's possible for them to not save the world, but also let them know that if they get their shit together and act like fucking badasses, they can fix what they broke. Sometimes. Other times, you waste The Blades of Bone and Flame and you don't have them when you need them because you wanted to open doors like Obi-Wan and Qui-Gon did with their lightsabers and expended all their power.

Fourth thing. Ignore legendary actions. This is one I am struggling with. I like legendary actions, but I also don't like legendary actions. They make big deal foes like ancient dragons and Strahd more powerful and can keep them from being stunlocked in solo battles. But I also feel like that mechanic is too obviously a game mechanic. Like if you want Strahd to be resistant to stunlocking, instead of just letting him 3/day suddenly make saving throws he failed, just give him a magic item (see my earlier point about him reasonably having access to all magic items) that grants proficiency or advantage or something on his Wisdom saves. If a player throws a lightning bolt at a foe with legendary actions and they roll really good damage and the target fails the save, that's really fucking cool. When you then decide to use the legendary action because the full damage lightning bolt would kill the NPC and you say, "Uh, no, he doesn't fail his saving throw, because game." it feels way less cool and feels super game mechanicy. It's not some innate creature ability that grants this advantage, it's a very obvious game mechanic. So yeah, either be subtle about using legendary actions (don't tell the players the result of saves and then say but the enemy still saves), don't use them to negate player awesomeness (like when they roll almost max damage with a lightning bolt spell and would kill a foe), or don't use them period.

Fifth thing. This is a holdover from 4th Edition that I really like. Use minions. Add enemies to an encounter specifically for the purposes of having players one shot them. Stat them out normally, allow them to deal damage and wear armor and all that, but have them die if they get hit. This gives the players that sense of being badasses and wading through enemies and hacking them down. It can also be used to increase the challenge of an encounter because these enemies can still hit the players. Be careful that they're not too hard to hit though. Having only one hit point doesn't matter if you can't get hit. Also, make sure that it is somewhat obvious that these guys are minions. 

So there are a lot of words about building encounters. None of it is perfect. None of it is guaranteed to work. Some of it is random thoughts that occurred to me while writing it. Some of it may be of value to you. Some of it I've used before to great success (or failure). Some of it I don't even agree with. Some of it doesn't even make sense. The thing to remember is that it is your game. Do what works for you and your players. If they or you want a sense of realism, make weapons and armor break. If they find it irritating instead of challenging, maybe don't do that. If your players don't care when you are obvious about using a legendary action, use them and don't worry about how game mechanicy it feels. If your players don't care about the environment around their characters, don't worry about putting cool things in it for them to interact with it. If your players are bored by combat because combat is innately boring to them, make a campaign about politics and dialogue and whatever they are interested in playing. Find the right mix of nonsense that you can all agree on enough to sit down at the table regularly to chuck dice at one another while pretending to be elves. Not everything is going to work for every DM and every player. Talk with each other and find what does. Ask players after the session what they thought of the horde of undead only the Cleric could get them through. Ask them what they thought of the fireball scorching their bowstring. Test things out, get feedback, and move from there.

Fuck, that was a lot of words.