Wonderweiss Margela

is an Arrancar in Sōsuke Aizen's army. Though not an Espada, Soul Society ranks his Spiritual Energy in the same class as them.

Appearence
Wonderweiss is small, thin, and somewhat child-like. He has light blond hair, parted on the die, with the tips fanning out. His hollow mask is a three-point tiara on the top of his head. He wears the Arrancar jacket with a hole in the middle of his chest, revealing his hollow hole. The outfit also has large arm cuffs on the sleeves. He only has two teeth visible when smiling and bright purple eyes.

Even though his body was wrapped in bandages during his birth, as a hollow he was roughly human-sized with several protrusions throughout his body. This leaves us to believe he was a Vasto Lorde.

Personality
Wonderweiss's personality is child-like and even autistic. When sent on a mission to kill, he instead plays around with a dragonfly. He shows a bit of hostility, firing a retaliatory Bala blast at one point, but quickly reverts back to his regular state after doing so. He isn't able to speak clearly, only saying a few syllables at a time like a child would. The only coherent sentence he ever speaks is his own name, immediatley after being "reborn" as an Arrancar. Kaname Tōsen says that Wonderweiss, like himself, is a pure being (though he makes a point of wondering whether he is pure good or evil), which often tend to stick together, causing Wonderweiss to follow him everywhere when possible. For this reason, he tried to restrain Gin Ichimaru from getting closer to Tōsen, as Wonderweiss was wary of him.

Arrancar arc
Wonderweiss' first appearance occurs during his actual creation at the hands of Aizen, where his original form is observed wrapped in what appears to be bandages, with a barrier present surrounding him. Numerous Espada were present at his 'birth'. Wonderweiss was among the Arrancar present during the third invasion of Karakura Town, where comments made by Soul Soceity scientists suggest that his reiatsu is at a similar level to an Espada. For the most part he just played around, waiting for their mission to be over. This was until Kisuke Urahara intervened in Luppi's fight, causing Wonderweiss to attack with unforeseen ferocity. This can be explained by the boy's sudden interest in Urahara's hat. He only relents upon seeing his power emanate from his hand, intriguing him completely and ending his fight with the former captain. Urahara noted that he was confused on whether he should attack him or not, since he was powerful, but also seemingly innocent. Yammy Riyalgo then takes over where Wonderweiss left off. He is pulled back to Hueco Mundo via Negación once Ulquiorra Cifer completes his mission.

Ulquiorra brings the human Orihime Inoue to Hueco Mundo, and she is welcomed by Aizen, who has her restore Grimmjow Jaegerjaquez's arm as a demonstration of her power. Wonderweiss also witnesses this and Grimmjow subsequently impaling Luppi with his restored arm (and power), killing him and regaining his former rank.

Hueco Mundo arc
When Ichigo Kurosaki, Uryū Ishida, Yasutora Sado, Renji Abarai, and Rukia Kuchiki invade Hueco Mundo, Wonderweiss is with Kaname Tōsen, who is monitoring the intruders' activities. When Gin Ichimaru walks in, Wonderweiss stops him, due to feeling uneasy about him. Tōsen explains that he believes Wonderweiss is a pure being, which is why he follows Tōsen (although he admits that he doesn't know if Wonderweiss is good or evil).

His whereabouts and activities after this are left unknown.

Powers & Abilities
High/Vast Spiritual Power: All of the arrancar invading Karakura in the third wave were as followed: Luppi the Sexta, Grimmjow the former Sexta and Yammy the Decima/Cero. By looking at this logically, Wonderweiss' spiritual power lies somewhere within the range of the 10th Espada all the way to the 6th; If anything else he should be at the Espada level of strength.

Bala: Hardens the users spiritual pressure and fires it from their fist like a bullet. The power emanating from his hand after his attack was pink and staticky, signifying his bala was/is pink.

Sonído: The Arrancar equivalent to Shunpo. Wonderweiss was able to sneak up on Kisuke and attack him with Bala, signifying his speed and use of Sonido.

Garganta: A method Hollows use to move from Hueco Mundo into the Human World. It tears the dimensional space and reveals a portal of whirling energy. Wonderweiss is able to move between worlds using this technique.

Zanpakutō
Wonderweiss's Zanpakutō is a large purple sword strapped to his back, about as tall as he is. The hilt resembles a western long sword rather than the more common katana, although the familiar hilt weaving is present, whilst the guard resembles an Egyptian eye. From a back view you can notice that the sheath represents a zweihinder. The name and released state of his Zanpakutō have not yet been revealed.

Trivia

 * Despite not being an Espada, many fans believe that Wonderweiss is a Vasto Lorde for numerous reasons. One of these is that Vasto Lorde are said to appear almost completely humanoid, which seems to describe what is seen of his original form. Additionally, Soul Society compares his reiatsu as that of an Espada, and Kisuke Urahara states that he was not sure if he could fight him because he was innocent looking but powerful.
 * Wonderweiss is the only non-Fracción Número with a last name.