|Bunch of apes earning pips to their Intelligence.|
Improving an ability score needs a certain number of pips depending on its current value:
- Leveling up grants one pip to a Prime Requisite. If there are multiple Prime Requisites, choose randomly which one increases. If a Prime Requisite is 18 it can't be increased and the pip goes to another, randomly chosen ability score.
- Achieving certain deeds grant one to three pips to a corresponding ability score, depending on the difficulty and scale of the deed.
The latter includes eating powerful creatures, interacting with alien objects, performing esoteric trials, succeeding at difficult tasks, dealing with deities and demigods, visiting hard to reach landmarks, training with legendary masters, and so on. A few examples from my campaign:
- Eating a giant's flesh increases Strength.
- Impaling yourself to a tree for nine days increases Wisdom.
- Looking into the black monolith without going insane increases Intelligence.
- Taking bath in the thermal pools of the Moon increases Constitution.
I keep the possible achievements secret, thus the player characters have to learn them from rumors, mentors, journals, or by experimenting. Sometimes if the player character does something amazing or surprising, I hand out one on the fly and add itt to my list.
There are a few limits of course:
- The maximum ability score is still 18.
- Performing a deed is only worth a pip for the first time.
So far this method worked fine for us. I'm not afraid that it will create game-breaking characters on the long, because the importance of ability scores and their modifiers is diminished at higher levels, and there are plenty of opportunities for my players to decrease their ability scores.