Aya Tokoyogi

Aya Tokoyogi is the main antagonist of the _Fiesta For the Observers_ arc in the anime/light novel series Strike the Blood.

Prior to the events of the Fiesta For the Observers arc, she was imprisoned within the Prison Barrier due to crimes that aren't mentioned or known but are considerably vile enough for the fact she was imprisoned for eternity among monsters and other dangerous supernatural criminals.