Anima is the "life force" of Ankhet, and most actions in the game will use some of this anima. The anima cost of an action is displayed in parentheses to the right hand side of an action button.
Anima can be regained in several ways. The most prominent of these ways is by resting, waiting for rollover, or getting it from other players.
Note: Patrons of Hathor and Ahmose get Anima back from the sphinxes