Rukia continues to struggle against Kaien, and he begins to overpower her when he uses the shikai of his zanpakutō. When Kaien disarms her, Rukia attempts to use a kidō spell, and reveals in the process that Kaien is afraid of the sunlight. Armed with this knowledge, Rukia binds Kaien with kidō and blasts a hole in the wall. In the sunlight, Kaien's face melts away to reveal a glass case with two masks inside. The creature reintroduces himself as Aaroniero, and after moving out of the sunlight, assumes Kaien's appearance again. After informing Rukia that he absorbed Kaien's remains when he came to Hueco Mundo, Aaroniero releases his zanpakutō, transforming his lower body into a giant, octopus-like form.