Board Thread:General Discussion/@comment-6057702-20130802173149/@comment-11051098-20130802210716

I dunno about the manga, but in the anime, Aaroniero told Rukia he was the only Gillian who was also a member of the Espada. I understood that he was still a Gillian.

He said that he gained Metastacia's ability of consuming the powers of every Hollow he devoured. I think that's why he was an Espada while still being a Gillian. He probably found a way to gain a human form and size, and managed to suppress all the power he had and further gained into a human sized body, which made him strong enough to become an Espada.

I think he also said that the form he gained upon releasing his Resurrectión, was a result of the more than 33.650 Hollows he had devoured. Sort of an army of 33.650 Hollows in 1 huge body.