Wonderweiss Margera is an arrancar in Sōsuke Aizens army who possesses a spiritual power that ranks him among the Espada, despite not being one himself. He has a child-like appearance with a small frame and resembles a tiara or crown on top of his head due to what remains of his hollow mask. Wonderweisss personality is also child-like and even autistic, which causes him to behave in an unusual manner when sent on missions. For instance, instead of focusing on the task at hand, he plays around with a dragonfly. He shows some hostility by firing a bala blast once but quickly returns to his usual state afterward. Wonderweiss is not able to speak clearly and only utters a few syllables like a child would. Kaname Tōsen describes him as a pure being who tends to stick together with others of the same kind, causing Wonderweiss to follow Tōsen everywhere possible. He also tried to keep Gin Ichimaru away from Tōsen due to his wariness towards him. Wonderweiss carries a large purple sword strapped to his back that is about as tall as he is and resembles a western long sword with an Egyptian eye-like guard. The name and released state of his zanpakutō are not yet known.
It is revealed in the "Fake Karakura Town" arc that Wonderweiss is a so-called "modified arancar", and that he was specifically created for the sole f