Kriemhild Gretchen is the witch form of Madoka Kaname in Puella Magi Madoka Magica.
Biography[]
So far, Gretchen has only appeared in timelines where Madoka ended up succumbing to despair and turning into a witch, all of which were ultimately undone by Homura's time-travelling abilities. All of which had her manifest as a colossal humanoid the size of a mountain with a shadowy figure resemblant of Madoka resting on top of her. She is indicated to be the most powerful witch in history, having possessed magic so great that she could destroy an entire planet with ease, according to Kyubey.