Gather Together! Group of the Strongest Shinigami

Aizen defeats Komamura with an extremely powerful kidou spell and continues his explanation by revealing he arranged Rukia's execution to obtain the Hougyoku, an orb that would allow him to gain hollow powers that was hidden in Rukia's gigai by Urahara. After extracting the Hougyoku from her body, Aizen orders Ichimaru to kill Rukia before Byakuya saves her as the majority of the Thirteen Court Guard Squads then arrive to restrain Aizen. But Aizen and his accomplices use several hollows to escape into the hollows' world Hueco Mundo. Afterwards, as Byakuya recovers, he explains to Rukia that he married her sister, Hisana, and adopted Rukia into the Kuchiki clan as Hisana's dying wish. But explaining that as he promised his parents to uphold the law without question as he broke his clan's rules in adopting her, Byakuya admits that he was conflicted between following the rules and allowing Rukia's execution or breaking them to save her.