Aaroniero is a minor antagonist from the series Bleach. He is ranked the 9th espada among Aizen's arrancar army and not like a traditional arrancar like his comrades. In his past he was a Gillian hollow before joining Aizen, he is an amalgamation of countless other hollows in one that Aaroniero devoured with his zanpakutou including one who had devoured a particular soul reaper named Kaien Shiba, displaying that he can transform into the likeness of others even Kaien.

Aaroniero is garbed in a long white arrancar robe and hakama with a large frilly collar that helps conceal part of the cylindrical jar filled with red liquid that contains both ball-shaped heads of Aaro and Niero, both of which possess individual personalities. Unlike other arrancar whose zanpakutou are swords, his is solely a tentacle appendage with a gaping mouth concealed in his sleeve in place of a forearm. Upon going into resurreccion form, Glotoneria, the only difference is Aaroniero's lower body is replaced and infused to a purple fleshy mass of numerous octopus tentacles as well as sinular eyes on two sides of the mass which have individual gaping mouths.

Despite not being like a traditional arrancar, he still also possesses natural abilities as one likely able to use a Cero even. His more notable means of attack of devouring his target through the use of his zanpakutou and ultimately inherit their ability.