I have a lot of tweaks and nerfs and what have you for core Pathfinder's rules in my campaign setting. Cary always whines about it. It's adorable. Like he thinks he's people or something. To be fair, he's right. I have a lot of rules stuff in my head and not on paper because I'm pretty much of the mindset that I'm not adding more shit to the Pathfinder campaign book until I know for certain I want to continue using Pathfinder rules for Hekinoe (spoiler alert: I don't). I'd feel worse about the handful or surprise rules I've had to inform people about, but I don't care. That's the risk you take in participating in a beta.
In addition to the rules that rattle around in my head because I'm not spending more time and effort on Pathfinder than I already do, there are also background rules. Rules I have in my brain hole that exist because of background material, but I choose not to implement because this is in fact a game and hammering more nails in the coffin of player choice and wish fulfillment doesn't really do it for me. Or they just add a bunch of work to implement.
All Nel Are More Powerful than the PCs
All Nel older than the player characters are at least of equal level with the PCs, plus one level per century of life.
Armor As Damage Reduction
All armor uses the armor as damage reduction rules from Ultimate Combat.
We'll be using my corruption rules instead of warped flesh feats. They are clunky, aggressively penalizing, and really bog down gameplay.
Elduman cannot use arcane classes (any class that has spellcasting ability, spell-like abilities, or extraordinary or supernatural abilities that are arcane in origin, subject to GM fiat).
There is no such thing as electricity damage. Anything dealing electricity damage now deals half the listed amount of electricity damage as fire damage, plus a stun/daze/something effect. Creatures that are not bioelectric organisms ignore this stunning effect, and creatures that do not conduct electricity (like golems and such or people wearing full rubber gimp suits) are immune to electricity powers. Electricity is not removed as a descriptor.
Fire subtype creatures lose their vulnerability to cold and gain vulnerability to water.
Only Fell Human Descendants, Fell Humans, Fell Soulless, Sereth, and Vyanth may have levels in Bard, Sorcerer, and Summoner.
If you don't pay a basic wage for an untrained hireling to your followers along with providing housing, gear, and food, you gain a -1 modifier to your leadership score. Because you're an asshole. If your followers are expected to risk their lives in service to you, or regularly do, the modifier becomes -2. This penalty is removed when you start paying them.
No race can use psionic classes (any class that has manifesting ability, psi-like abilities, ki points, or extraordinary or supernatural abilities that are psionic in origin, subject to GM fiat) except Elduman, Elduman descended Uncout, and Rankethlek. This does not exclude all races except Elduman from being Monks, as there is a Monk archetype that does not gain ki abilities, psi-like abilities, or extraordinary/supernatural abilities with a psionic source.
Rankethlek cannot use arcane classes (any class that has spellcasting ability, spell-like abilities, or extraordinary or supernatural abilities that are arcane in origin, subject to GM fiat).
Rankethlek only have energy affinity with electricity, so their energy bolt/line/etc spells may only use the electricity option.
Summon Monster I - IX no longer exist. Instead, they are replaced with the an arcane version of the astral construct power. The arcane version of astral construct (sorcerous construct) will appear somewhere at some point to be read and used as a guideline. Additionally, any spell that creates a creature out of magic (which is what all summoning spells do in Hekinoe) is vulnerable to ant-magic and detect magic. Detect magic shows the creature to be a sorcerous construct, and when such creatures enter an area of anti-magic, their creator must make a Will save, or the energies constructing them are immediately dispersed.
Thrallherd is straight up mental enslavement, and the Elduman frown heavily upon it.
Thrallherd believers and thralls cannot be Elduman, Rankthlek, any race/class that gains power resistance, or any class that has a +2 Will save bonus at 1st level, or have a Wisdom score of 11 or higher.
Use Magic Device
Elduman and Rankethlek cannot use Use Magic Device on sorcerous devices. Non-Eldumans and Non-Rankethlek have the same restriction when attempting to Use Magic Device on a psionic device.
Limited wish and wish, along with their psionic equivalents (reality revision?) do not do whatever you want. They can increase stats, duplicate other spells/powers, and the other stuff clearly outlined in the descriptions, but you can't get into outlining your own specific wishes for things.
Always bear in mind, you guys are basically in a beta and things could always be worse. Hehehe.