The true Holy Mother of Darkness is the protagonist and surprise villainess of the manga story "Ikei Seibo" (異形聖母) by Hashiba Sunanin (羽柴砂忍).
A blonde nun, the protagonist is abducted by a mysterious brunette woman who is seeking to become the the crimson woman from the Book of Revelations. The nun is tortured and threatened into complying, but when she finally does, she reveals that she, in fact, is the true whore of Babylon. She then transforms into an angel as the brunette woman is devoured by the summoned beast.
Gallery[]
Holding the brunette's severed head in her hand...