Kiyone Kotetsu

is the co-3rd seated officer/acting lieutenant of the Thirteenth Division in the Gotei 13 under Captain Jūshirō Ukitake, sharing her position with Sentarō Kotsubaki.

Character Outline
Kiyone is the younger sister of Isane Kotetsu, the Lieutenant of the Fourth Division (the medical and supply relief division). Unlike her sister, Kiyone is very open and excitable but she does share Isane's sense of loyalty.

She holds her captain, Jūshirō Ukitake in high regard and always tries to impress him anyway possible, even if she has to ruin her partner Sentarō Kotsubaki to do so. Like other female Shinigami she is a member of the Shinigami Women's Association.

Kiyone's infatuation with her Captain is often a source of comic relief, as she frequently engages in competition with Sentaro over who admires and/or loves him more, much to Ukitake's exasperation. In one omake chapter, she is even willing to help Soifon pin Ukitake to a tree with kunai knives and slash open his clothing so she can have "sexy" photos of him, although she does jabber "I'm sorry, I'm sorry!" while she photographs him.

History
Not much is known about Kiyone's history, except that she was already in the 13th Division when Rukia Kuchiki joined them. According to Lieutenant Kaien Shiba, sometimes both she and Sentarō would occasionally show up on duty while drunk. It is unknown what her rank was back while Kaien and Miyako were still alive, but she (along with Sentarō) became a 3rd Seat officer sometime before the main storyline.

Synopsis
Kiyone first appears alongside Sentarō Kotsubaki when they inform their captain, Jūshirō Ukitake about Sōsuke Aizen's death. Both Kiyone and Sentarō decide to take the blame for delaying the message from getting to Ukitake. Later, she and Sentarō follow Ukitake when he stops Byakuya Kuchiki from killing Ganju Shiba and Hanatarō Yamada. They don't show themselves until after Byakuya leaves. Ukitake orders Sentarō to take Rukia back into her cell and Kiyone to bring a Fourth Division medic to treat Ganju's wounds.

Later, she and Sentarō are speaking to Retsu Unohana about Hanatarō's involvement with the Ryoka, stating that he was forced into helping them.

When Rukia's execution is moved up and finalized by the Central 46, Ukitake, knowing that his appeals to them have failed, decides to save Rukia himself, and Kiyone and Sentarō decide to follow him. They arrive at Sōkyoku Hill, and Shunsui Kyōraku assists Ukitake in destroying the Sōkyoku. After Renji Abarai escapes with Rukia, and Ichigo Kurosaki begins battling Byakuya, Kiyone tries to help Isane, but as soon as Shigekuni Yamamoto-Genryūsai decides to punish Ukitake and Kyōraku for their actions in Rukia's escape. Kyōraku drags Ukitake away, knowing that fighting Yamamoto would risk any bystanders nearby. As Ukitake and Kyōraku run, Soifon nearly kills Kiyone for her actions. She is saved by Yoruichi Shihōin, who drags Soifon elsewhere for battle.

Once the danger is passed, Kiyone is taken to the 4th Division by Unohana to recover from her injuries from Soifon. She later learns of Aizen's betrayal while in recovery from Isane's message.

Trivia

 * Interestingly, in the second intro to Bleach, despite being shown only briefly, Kiyone had silver-colored hair like Isane.