Class

The class of a Character is determined by their Class Mod and signifcatly influences their appearance (what else?)

You may only change your class when inside a Saeva Tent or otherwise close to Botsy.

Samplers
Samplers are special classes that are scheduled to be added to the game at a later point in time.

When a Sampler Core Mod is equipped, that character's auxiliary Mod slots are replaced with Beat slots. This allows a single character to equip three Mods at once and mix two of them together per turn in combat, enabling some righteous combinations. There is only one sampler Core Mod for each character.