Chaos Controller

Chaos Controller is the rare upgrade rewarded by completing the Chaos Device sidequest. It permanently unlocks the full cross-class ability pool at level-up — every class's abilities become available as options, not just your cat's starting class — and grants extra rerolls to find the right pick. Part of the Experimental item set, it's one of the most powerful build-shaping items in the game, letting you stack the best abilities from any class without being locked into a single archetype.