Aaroniero Arruruerie

Aaroniero Arruruerie is an Arrancar in Sosuke Aizen's army and the Noveno Espada.

Aaroniero is present when Sōsuke Aizen is creating Wonderweiss Margela. He only stands and watches, with the upper half of his body covered in shadow, without his mask.

He puts his mask on when the Espada are gathered by Aizen about Ichigo Kurosaki, Yasutora Sado, and Uryu Ishida entering Hueco Mundo to save Orihime Inoue. He sits between Tier Harribel and Yammy Llargo and complains about the intruders, along with Baraggan Louisenbairn, Szayelaporro Granz, Yammy and Nnoitra Gilga.

Rukia Kuchiki encounters Aaroniero on the bridge outside his palace. He leads her inside the dark tower and explains that he cannot stand sunlight. He takes off his mask while introducing himself as the 9th Espada, Aaroniero Arruruerie, who, upon removing his mask, is immediately recognized by Rukia as Kaien Shiba. Rukia is confused by the sight of her deceased mentor. Aaroniero pulls out a cushion and tells her to sit, as they have much to discuss.

Aaroniero then explains to her that the night he was possessed, his spirit began to crumble after the battle and by the time she had brought his lifeless body back to the Shiba house, it had completely shattered, and from there it was thrown into Hueco Mundo. He explains that the Hollow he fought was one of Aizen's experiments and that every time it was destroyed, it would come back to Hueco Mundo and regenerate. However, since the Hollow had fused with him, the regeneration restored his body, but instead of the Hollow being in control, he was. At first, Rukia has a hard time believing such a thing, but Aaroniero assures her that he is serious. He then explains that as he ended up taking control of his body again, he went on to become an Espada to aid in his revenge against Aizen. Aaroniero states that the blue sky outside is the dome of Las Noches created by Aizen and that the light of the blue sky allows Aizen to see anywhere he wishes.

He then tells her there is a mission of great importance that only she can carry out and they will talk further in a different location. He then takes out his Zanpakutō and attacks her. Rukia becomes confused and listens to him speak so coldly about her involvement in his death, and resigns herself to be a just sacrifice for what she did to him and willingly offers her life to him. But she relents and states that she has come there to save Orihime and that until she does, she cannot give her life to him. He tells her that he was only joking, but there is something only she can do for him if she is to truly sorry for what she did. He asks her to kill her friends, and Rukia quickly realizes something is wrong and that he cannot be who he claims to be, as Kaien would never ask her to do such a thing. She releases her Zanpakutō, Sode no Shirayuki and begins to attack him.

The two engage in battle for a brief period, with Aaroniero goading her with his knowledge of her fighting style. He then releases Kaien's Zanpakutō, Nejibana and begins to relentlessly attack Rukia. As such, Aaroniero uses Kaien's Zanpakutō to easily overpower her in the course of their battle. Rukia eventually concludes that everything Aaroniero said was a lie and notices him running from the sunlight when a wall is damaged. She uses a Kidō combination to restrain him and then blows a hole in the wall, forcing him to remain in the sunlight; thus revealing Aaroniero's true face - a cylinder filled with liquid containing two small, floating heads inside.

Aaroniero then reveals that had she used her Kidō to attack him directly, she might have actually hurt him. Rukia claims that now that she knows that he is not Kaien, she will not have to hold back anymore. Aaroniero questions if she thinks that holding back is really what kept her from actually harming him. He then explains that although he can't use his powers in sunlight, all he needs is the shadows and he can use it again as many times as he wants, as he resumes Kaien's form. He then comments on the annoyance of the sun under the dome of Las Noches as his powers only work in the darkness. Aaroniero then corrects her previous assumption that his power was transformation, as he is the only Gillian-class Menos Hollow out of all the Espada. In general, no Gillian would be powerful enough to join the ranks of the Espada. Yet he is an Espada because he is the only Arrancar in existence that has limitless potential for evolution. He reveals that his original story about what happened after Kaien's spirit died was partially true. In fact, Aaroniero consumed the Hollow Metastacia and absorbed its ability. It was through eating that Hollow and gaining its abilities that he gained access to Kaien's body. He then reveals his Zanpakutō, Glotonería, as he explains that he, in fact, is using the spirit body of Kaien Shiba and all his experiences and memories are still intact. Aaroniero was using them to impersonate Kaien and manipulate Rukia in turn. Rukia noticeably gives up her will to fight upon seeing his form and realizing the ramifications of his words. Aaroniero releases his Zanpakutō and impales Rukia on the end of Nejibana.

Aaroniero notices that Rukia is still conscious and states the it is admirable that she fights for survival, but it is pointless as she can never strike him down. Rukia grabs Nejibana and states that she just remembered as she lifts her sword to his face. Aaroniero makes fun of her asking if she remembered how to pretend to fight with a broken sword. Rukia then reveals her San no mai, Shirafune technique, which impales Aaroniero through his head. The bottom face dies, screaming in agony while feeling betrayed by Aizen's promise that he would never be in pain again, while the top face curses one last time before splitting in half.

In the Legacy of Chris Thorndyke,

And he is reprised by Keith Silverstein as deep voiced and Wendee Lee as high voiced in the English dub and Ryuzaburo Otomo as deep voiced and Mayumi Tayaguchi as high voiced in the Japanese dub.