Teresa Beria

A Serbian Orthodox nun that serves at St. Mihailov in a variety of ordinary chores, such as taking care of children in the school's kindergarten or tending to flowers, she is notable in that, for most of the beginning of the series, she never shows any form of emotion, reacting with fright only when Mafuyu was about to close a door on her. This is explained when her past is revealed: as a child she was part of a Serbian Orthodox convent in Krajina, during the Yugoslav Wars, a jovial and hyperactive girl until the day a group of Croatian militiamen, led by "Gas Chamber" Croa, assaulted the convent and pillaged it, slaughtering and raping its occupants in a bloody carnage.

The sole survivor, Teresa assisted at the whole massacre from inside a closet, and when found, she was so shocked that her emotions were locked away by the trauma. Only when Sasha gave her his support and they both avenged the slaughter by killing Croa, did she manage to smile for the first time in years. Teresa used to offer her Soma to Sasha, but since Ootori's death she partners with Lizzy. While an ordinary human, Teresa is well-versed in combat, using a bow for long-range attacks or fighting bare-handed, using blades concealed in her gown.

A running gag involves two curious flocks of hair that she has on her head, which look and behave like a puppy's ears, flipping when she is happy or excited, dropping loose when she is embarrassed, and so on.