Teresa secretly has a crush on Sasha. She never shows it though..
Even when assigned to Elizabeth and knowing how Sasha and Mafuyu feel for one another, Teresa doesn't let that stop her from helping Sasha when she cans, and expressing her affection simply by being his Maria.
Later into the story Teresa become Elizabeth Maria, though she occasionally returns to supporting Sasha when Mafuyu is assigned to another Qwaser. Elizabeth and Teresa grow quite close, sharing an adventure in Lesbos as well as taking down their parental figures' clones together in the last arc of the manga.
Sister Wilma Edit
The nun who looked after her when she was a young girl, Teresa is still traumatized by what rapists did to her simply for being of a different race. Later, when the Theosis Project produces a clone of Sister Wilma, Teresa is briefly tricked into letting her guard down around her, leading to further problems as Sasha was being framed by the Qwaser clone in Wilma-2's care.