Walpurgisnacht (ワルプルギスの夜 Warupurugisu no Yoru, "Night of Walpurgis" or "Walpurgis Night") is supposedly the strongest witch current magical girls would have to fight. Her real name is unknown, while "Walpurgisnacht" is a common moniker given to it by magical girls. Her nature had been kept mysterious during most of the series, which led to a lot of speculation from fans during the original broadcast.
more info: http://wiki.puella-magi.net/Walpurgisnacht
So I built this with DB12 in mind so yeah. maybe I should've gone with the ELS stuff from Gundam 00 meh. Couldn't quite finish it due to the cpu cap so yeah. It appeared in the movie version of Puella Magi Madoka Magica
also I just realized that her corset thing is supposed to be that green beige color thing