"Thieves are agile, dagger-wielding dark elves that specialize in high-speed attacks and aerial combat. The class is currently under development and was revealed at the 2009 Dungeon & Fighter Festival.
Thieves are able to advance to one of four forms. Rogues specialize in close-range combat and are skilled at dodging. Necromancers make use of the dark powers inherited from their dark elven blood, and are able to do battle with the aid of an undead servant. Kunoichi move quickly and utilize long-range and wide-area magic spells. Shadow Dancers rely on stealth and assassination techniques."
Thief Promotion Video
Rogue Promo Video
Necromancer Promo Video
Currently with the patch only 2 of its sub-classes are out.