Isane Kotetsu

"The delicate Lieutenant that does not seem as such from her appearance. She cannot sleep after getting a nightmare. Kamaboko?" - picture caption by Tite Kubo

is the lieutenant of the 4th Division formerly under Captain Retsu Unohana. She is also the older sister of the 13th Division's 3rd Seat, Kiyone Kotetsu.

Appearance
Isane is a tall, young looking woman with gray eyes and short messy silver hair with strands on the right side of her face that are shoulder-length and styled as two thin braids. She wears a thin dangling red earring on each ear and a standard Shinigami uniform with her lieutenant badge on her left arm.

Personality
Isane is generally quiet and observant, with a strong sense of loyalty. She can be impatient in the face of an enemy, rushing after enemies she has no chance of defeating, including the seemingly unstoppable Sōsuke Aizen. She looks to Unohana as a mentor and mother figure. It is noted by Unohana that Isane suffers from frequent and recurring nightmares, which are often odd or whimsical in their contents. For example, she once had a nightmare involving kamaboko (a fishcake made of pureed surimi), which she intensely dislikes. Also according to Unohana, she rarely talks in a girly manner. Her favorite food, on the other hand, is porridge, to the extent that she is capable of eating it as the three main meals on the same day.

When Isane has time off, she goes to see her sister Kiyone and vice-versa. They are very close sisters who enjoy meeting up and having fun together. Recently, her favorite place to hang out is the Kuchiki estate, in the "secret base of the Shinigami Women's Association". She is a notable member of the latter Association, where her meek nature occasionally gets her in trouble with group activities including getting captured alongside Nemu Kurotsuchi when attempting to take a picture of Byakuya Kuchiki.

Believing that the nutrient level of porridge is very low, Isane started eating porridge when she passed 170 cm in height as she did not want to get any taller. However, she did not stop until reaching 187 cm, her height being another source of frustration for her. Once, after hearing of how sleeping helps children grow, she decides to not sleep again in order to halt her growth. During a meeting of the Shinigami Women's Association, she proposes a Denreishinki sturdy enough to not break if it is dropped from a height of 2 meters, only to be told by Nanao Ise that it is not a common problem.

Soul Society arc
Isane is mostly seen around Retsu Unohana. She is present when Unohana confirms to Sajin Komamura and Kaname Tōsen that Aizen is dead. When Hanatarō Yamada went back to the 4th Division after he met with Jūshirō Ukitake, he gets in trouble with his captain. However, when Isane is walking with him afterwards, Hanatarō asks if what he had done was wrong, and Isane answers he was brave for what he did.

Isane attends the execution of Rukia Kuchiki with her captain on the Sōkyoku Hill as well as her rescue by Ichigo Kurosaki. She appears upset by Genryūsai Shigekuni Yamamoto's false promise to allow Rukia's would-be rescuers to leave safely after her execution, but Unohana tells her that he said it so she could die in peace. After Rukia is handed off to Renji Abarai to get away, Isane hesitantly joins with Chōjirō Sasakibe and Marechiyo Ōmaeda after them. She releases her Zanpakutō to fight against Ichigo Kurosaki, but is taken down, albeit much lighter than the other two. After her defeat, her sister Kiyone runs over to aid her, but Suì-Fēng intercepts her and knocks her to the ground. If not for the fast action of Yoruichi Shihōin, Kiyone would have been killed.

Unohana picks up Isane, and when she starts to apologize for failing to defeat Ichigo, Unohana tells her to calm down. After dropping the wounded off, Isane and Unohana quickly head to Central 46. They arrive at the scene in time to see Aizen defeat Tōshirō Hitsugaya. Captain Unohana announces her presence to the traitors while citing her own suspicions surrounding Aizen's staged death. She also goes on to claim that the Offices of Central 46 Chambers was the only place he could hide and mentions the use of an elaborate corpse doll on his part. Aizen then points out the mistakes in her analysis, while also commending her for seeing through his deception. Isane learns of Sōsuke Aizen's betrayal, and reveals that she and the other lieutenants thought Kyōka Suigetsu was a running water-type Zanpakutō, not one with the ability of perfect hypnosis.

Isane prepares to attack Aizen, but he and Gin Ichimaru quickly get away before she can get near them. Unohana then instructs Isane to use her Kidō skills, both in tracking down Aizen and communicating with the remainder of Soul Society, as well as the Ryoka, on the emergent schemes of the traitorous captain.

After the end of the incident, Isane assists the rest of her squad in healing the wounded. In the middle of the night, she wakes up while having a nightmare about fish paste. She wanders out to get some air while trying to decide what to do, only to be discovered by her captain, who gently tells her to get some sleep. .

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

Hueco Mundo arc
Isane arrives in Hueco Mundo with her captain, Hanatarō Yamada, Byakuya Kuchiki, Kenpachi Zaraki, Yachiru Kusajishi, Mayuri Kurotsuchi, and Nemu Kurotsuchi. When Isane and Unohana arrive, they are met by Rudbornn Chelute and the Exequias, who flee after hearing Retsu Unohana is a captain. Isane prepares to chase after them, but Unohana stops her. She and Unohana proceed to heal Yasutora Sado and Gantenbainne Mosqueda. She later tracks down Byakuya's location and does not appear until after his battle with the 7th Espada Zommari Rureaux. She then proceeds to heal Hanatarō and Rukia.

Fake Karakura Town arc
After Mayuri Kurotsuchi announces that he can get Ichigo Kurosaki back to the Human World with a Garganta, Unohana offers to accompany Ichigo back to Karakura Town. Before they leave, she orders Isane to assist Byakuya and the remaining forces in Las Noches. After Aizen is defeated by Ichigo, Isane returns to the Soul Society via Garganta along with Hanatarō, Byakuya and Zaraki.

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

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

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

The Thousand-Year Blood War arc
After the release of Genryūsai Shigekuni Yamamoto's Bankai during his battle with Yhwach, Isane notes that her skin had suddenly become dry, to which Unohana remarks that she had said something really girly, greatly embarrassing Isane. Isane stays within the 4th Division's building with Unohana throughout the Wandenreich incursion. After the enemy departs, the rattled Isane begins to question if staying inside was the right thing to when so many people were dying. Gently berating her, Unohana tells Isane to not act based on her emotions. Breaking into tears, Isane is then reminded that it was the Captain-Commander's last order for them to remain inside. Later, she stands looking out the window, clutching onto a note left to her by Unohana before bursting into tears.

Later, Isane bears witness to the swift and complete invasion of Soul Society by the Wandenreich. The next day, Rukia Kuchiki brings a grievously injured Captain Rōjūrō Ōtoribashi to her for urgent medical care and Isane sets about healing him. While Isane is healing, Yachiru Kusajishi, who she had enlisted to help her, comes and brings her beds to lay the wounded on. Telling Yachiru to be quieter so they aren't noticed, Isane apologizes for giving her such a dangerous job. When Isane thinks it's a miracle Yachiru hasn't been found considering how loud she is, she is surprised by a voice coming seemingly from nowhere which correctly deduces her thoughts. Trying to locate the voice's origin, Isane is asked where she is looking as Sternritter V, Guenael, appears behind her and grabs her. The Sternritter is punched away by Yachiru, making him disappear. When Yachiru is hit by the Sternritter, Isane runs over to her. She then listens to Guenael introducing himself and his power.

Powers & Abilities
Kidō Expert: Isane is shown to be highly proficient in Kidō spells, apparently excelling in chaining multiple spells together for various effects. While being the second most proficient in healing Kidō in the 4th Division, she has good understanding of binding spells as well. She is also shown using Hadō #1 Shō and #31 Shakkahō, revealing that she is skilled in the use of destructive spells as well.

Expert Healer: As the lieutenant of the 4th Division, Isane excels in healing techniques, being second in the 4th Division only to her captain. She is known for speedily providing medical attention.

Shunpo Practitioner: Isane is proficient enough in to keep up with her captain.

High Spiritual Power: Being a lieutenant of the Gotei 13, Isane boasts a high level of spiritual energy.

Zanpakutō
. In its sealed form, Itegumo takes the form of a katana with a deep blue handle and a pointed round guard, somewhat similar to a snowflake. It is kept sheathed on the left side of Isane's waist.


 * Shikai: Its Shikai command is . When its Shikai is activated, two smaller blades protrude from Itegumo's hilt at 45° angles.


 * Shikai Special Ability: Unknown


 * Bankai: Not Yet Achieved

Navigation
Isane Kotetsu Isane Kotetsu Isane Kotetsu