Subclasses
Every class has subclasses which add more specialization and flavour to the character. These subclasses level up when your class levels up (not your total character level). Certain classes unlock their subclasses at higher levels, while others might unlock at the lower levels.
While there are only a dozen or so classes for players to choose from, there are multitudes of subclasses to choose from.
d100
Mod
ADV/DIS