Its Cherry in her dark form. "Death Angel" is some sort of codename for her given by Dieter (the General) Neire and Nael are just 'modified' human, but Cherry is a complete bio-weapon. Unlike Neire and Nael, Cherry didn't know what she's doing after she transform and MUCH stronger than both of the boys. She can transform her hair/body into wings and any kind of weapon.
With her ultimate power she could blow the whole planet if she wanted to..so..that's why it is not recommended to let Cherry transform. Neire, Nael, Cherry, they all travel to find a way to deactivate her power completely.
Before she transforms: Other Dark forms:
*Genius Tablet *SAI & Photoscape *Cherry (Death Angel form) belongs to me
This is awesome! At the same tme I was looking at it, I was listening to a song, and for me it matches a lot for her, it's from ff xiii OST. ( [link]) It's silly, but, really, it was more amazing to watch at your picture! o_o