Undead are the ultimate undead warriors, arising from a dark ritual, making them ideal assassins: they know no fear, fatigue, or regret.
Blood Reapers are the elite vanguard of the undead legions. Reapers are born from irredeemable rage. These are the souls of former fallen commanders, whose anger was so great that it literally "ignited" their lifeless essence.
Grave Guards are the only creatures allowed to be in the personal chambers of the high liches. They are the ears and eyes of their master.
They are ideal bodyguards, whose existence is inextricably linked to the architecture of the Necropolis, as they are devoid of ambition, fear, and needs.