Isane Kotetsu/Anime Continuity

is the lieutenant of the 4th Division under Captain Retsu Unohana.

Bount arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

Isane makes several minor appearances in the Bount arc, notably along with her captain and 3rd Seat Yasochika Iemura healing wounded soldiers and later informing Tōshirō Hitsugaya of updates during Jin Kariya's invasion of the Seireitei. At the same time, she tries some of Rangiku's cooking, which tastes revolting based on a disgusted sound Isane makes.

Zanpakutō Unknown Tales arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

Isane appears with Momo Hinamori at the 10th Division office, surprised to find Rangiku's Zanpakutō sticking out of the ground. When Rangiku tells her that she is trying to communicate with her Zanpakutō, Isane tells her that her own Zanpakutō, Itegumo hasn't been responsive lately, something that has never happened with her before. Later, she is summoned along with most of the other high-ranking Shinigami to Sōkyoku Hill as Muramasa and the other manifested Zanpakutō Spirits appear before their former masters, and is ordered to treat Lieutenant Chōjirō Sasakibe after he is injured by the Zanpakutō. She and her captain are later visited by Nemu with a request by Mayuri Kurotsuchi that Unohana come to the 12th Division barracks. After Rukia is injured by Sode no Shirayuki, Isane is seen treating her as she wakes up. When Rukia asks about Ichigo's condition, Isane mentions that his location is unknown and no one can go looking for him with the current situation. However, Ichigo eventually returns on his own after subduing Zangetsu. She appears with Unohana later as she goes to tend the wounded. Though she tries to say something to her captain, she decides not to and leaves.

Later, she is out in the Seireitei, informing Lieutenant Tetsuzaemon Iba that Suì-Fēng and the Onmitsukidō have closed in on the Zanpakutō Spirits in the 6th Division's barracks. As they both decide assist them, they are confronted by Ashisogi Jizō. It tries to attack them with a blast of poison gas, but she uses a Shō Kidō spell to knock it away, and Tetsuzaemon uses his sword to cut down a building and trap it underneath the rubble. They try to leave to inform Mayuri about the situation, but are confronted by Haineko and Tobiume before they are able to leave. Ashisogi Jizō recovers as well. Isane tries to hit it with a Shakkahō Kidō spell, but it manages to avoid it and attacks her with several blades bursting through its front. Isane barely manages to block the blow, but is knocked backwards. While she tries to recover, she realizes that she can't move her legs. Tobiume explains that when Ashisogi strikes a limb, it becomes immobile, and that since Isane can't move her legs, Ashisogi Jizō's attack must have struck both of her legs. Despite her immobility, she tries to fight back against Tobiume, but the Zanpakutō Spirit avoids her attack and tries to retaliate. However, Momo Hinamori arrives to block the blow. Rangiku Matsumoto arrives as well and attempts to fight Haineko, but Ashisogi Jizō confronts them and spews a large cloud of poison at all four of the lieutenants. Tetsuzaemon and Rangiku then help an injured Isane to run away along with Hinamori, but Ashisogi Jizō assumes its Bankai form and pursues. Even though they manage to escape, the four lieutenants collapse, affected by the Zanpakutō's enhanced poison. Isane is later seen in the 4th Division Headquarters, receiving treatment.

Beast Swords arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

Isane comes into Nanao Ise's temporary office and offers her a box of cookies that Momo Hinamori made. When she is about to make tea for the two she notices that the tea leaves have vanished. She and Nanao then report this piece of information to the rest of the captains.

Gotei 13 Invading Army arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

Having been locked away by Kagerōza Inaba, Isane is freed by Yoruichi Shihōin and carries an injured Akon to the confrontation with Inaba. She later joins the other lieutenants in fighting the Reigai with the captains. Despite evening out the numbers, Isane and the other Shinigami are still pressured by the Reigai. With Byakuya injured, Reigai-Yumichika attacks her and keeps her occupied so that she is unable to heal him.