Each Species is either Undead or a Breather (living).
The Undead lose Vitae on a nightly basis and consume Vitae for casting spells (if used with Empower Magick Spellcasting HUD).
To replenish their Vitae, the undead must either spend time regenerating, or must feed upon the Vitae of others.
The HUD includes specific functions for the Undead to allow them to do this:
NEXT: Feeding