Each ability score has an associated ‘ability pool’ that may be used to fuel various character powers and talents.
The base value of each ability pool is the associated ability score modifier plus the character’s Level Bonus.
After each encounter each pool recovers a number of points equal to the base pool value to each pool. Points spent between encounters are recovered after the next encounter.
Ability Score Modification
Effects that in D&D 3.x would affect ability scores (such as ability score damage or drain, or apply a bonus to an ability score) now make the change to the character’s ability pool.
A casting of bull’s strength now provides a temporary bonus to the character’s Strength pool, a stirge’s bloodsucking ability does damage to the Constitution pool, and so on. If an ability pool is reduced to zero the creature will suffer a condition effect, and each multiple of the base score the creature’s ability pool goes negative the condition is made worse. For instance, a character with a Constitution pool of 10 might be fatigued at 0, exhausted at -10, and unconscious at -20.
Any conditions suffered as a result of pool reduction (expense or damage) remain until the pool is fully recovered.