At Level 10 you can choose between 4 classes : Mercenary, Assist, Acrobat and Magician.

Each classes have 2 evolutions at Level 50.

Mercenary can choose between Blade and Knight.

Assist can choose between Billposter and Ringmaster.

Acrobat can choose between Ranger and Jester.

Magician can choose between Elementor and Psykeeper.

Each class give you Prime Stats bonuses.

You lost your class when you activate Prestiges.