Theresa Apocalypse

Former S-Rank Schicksal Valkyrie. The best friend of Kiana's parents — Siegfried and Cecilia. Director of the Academy of St. Freya. Her physical development stopped forever at the level of a twelve-year-old girl. Sometimes she intentionally behaves like a child, trying to use it to her advantage. Takes care, of others and tries her best to protect them.

Teresa is a clone (dubbed A—310) created by Otto Apocalypse using the genes of a Honkai beast named "Vishnu" and the DNA of Kallen Kaslana in an attempt to revive the latter. Demonstrated excellent resistance to Honkai energy, and high combat power. Otto later adopted A-310 as his granddaughter, and gave her the name Theresa.