Nero

One of the seven Anticross

Spoiler

that doesn't exist in this world

. Also known as . The strongest and the worst Anticross possessing power comparable to that of Master Therion. She contracted with the Grimoire Unaussprechlichen Kulten (無名祭祀書 - The Book of Nameless Rituals) and summon Deus Machina Nameless One.

"How hateful... Don's just leave Nero out of the gang like that."

Spoiler

In truth she is the nightmare version of Nero brought by Another Blood as nightmare for her "story". Because of the despair memories that she had to endure in Infinite Spiral, she held a grudge towards her own son Master Therion himself, thus wanted to kill him for vengeance.