Kaien Shiba

"Kaien values friendship above everything else. His spirit of kindness lingers on today." - picture caption by Tite Kubo

was the Lieutenant of the 13th Division, under Jūshirō Ukitake, up until his death at the hands of a Hollow that also killed his wife, Miyako Shiba.

Personality
Kaien was an upbeat and kind young man from the Shiba house, tattooing his arm with the Shiba house symbol, who treated all his subordinates equally. He made friends very easily, earning the respect and trust of most fellow Shinigami with not only with his above-average combat prowess but mainly with his kind and honest nature. He especially treasures bonds with others, believing that "heart" exists in them and remains with people's comrades after people die, and as such, believes that people must not die alone.

It is known that his favorite food was ohagi, and he liked to take afternoon nap if he could.

Appearance
Kaien closely resembles Ichigo Kurosaki in both appearance and personality, and their resemblance is brought up multiple times in the series. While Rukia was training Ichigo she often became exasperated by his lack of understanding of things Kaien would have known, and Ukitake is stunned by Ichigo's appearance. Byakuya Kuchiki also notes the resemblance, even stating that Ichigo's attitude annoyed him as Kaien's had.

Strangely Kaien's siblings, Ganju and Kūkaku, do not remark upon or even openly notice Ichigo's resemblance to Kaien.

As of yet Ichigo is unaware of his resemblance to the late Kaien, but may know something about Rukia's relationship with him; when looking for Rukia, he knows she could only be at the Shiba manor after realizing that she is not in the Seireitei.

History
Kaien Shiba served as Lieutenant of the 13th Division under Jūshirō Ukitake, taking the position 108 years prior to the start of the story. When he was alive he often took over Ukitake’s duties because of the Captain’s illness.

Kaien was the oldest of the Shiba siblings, and grew up in Rukongai, though the Shiba house was once one of the great noble houses. His sister Kūkaku and their younger brother Ganju don’t like Shinigami very much, and they are still baffled by their older brother’s desire to become one. However, Kaien was a prodigy as a Shinigami. He completed the six year curriculum of the Shinigami Academy after only two year, and went on to become Lieutenant of the Thirteenth Division.

He was the first person in Seireitei to treat Rukia like an ordinary person since her adoption into the Kuchiki family. Until he came along, she was treated with careful respect to her face and talked about and bashed behind her back. She was grateful for that, and eventually fell in love with him. She didn’t pursue him because Kaien was already married to the third seat of the 13th Division, Miyako Shiba. However, Kaien did appear to take a special interest in Rukia, probably because of her detached and slightly depressed manner. Rukia tended to jump when she saw him, much to his irritation. She also followed him like a puppy following its master.

When Kaien’s wife died at the hands of a Hollow, Metastacia, Kaien swore revenge. Ukitake and Rukia accompanied him in his search. They found the Hollow in its lair, and Kaien asked for permission to fight it alone. Ukitake granted permission, and Rukia watched in horror as the Hollow’s abilities became apparent. Kaien’s Zanpakutō was broken as soon as he touched the Hollow. Kaien continued to fight it alone. It obviously pained him to not help his Lieutenant, but when Rukia asked why they could help Kaien, he told her that it would kill his pride. Rukia yells at her Captain, saying that pride isn’t important compared to life. He answers her calmly: “''Rukia, remember this. There are two types of fights. Whenever we are in battle, we must be one of the two. The fight for life or…the fight for pride! Right now…He is fighting for his pride! His wife’s pride…his men’s pride…Most importantly…his own personal pride. Dismiss this as his stubbornness…and let him fight alone like this…''”

Kaien held his own against the Hollow for several minutes before the Hollow revealed its true ability. It merged itself with Kaien, and when Ukitake stepped in, the Hollow laughed maliciously and told him that he and Kaien were now the same being, because they were both spirits. It wasn’t the same as possession.

Rukia, who had been Hollow-Kaien’s first target, was told to run while Ukitake held it off, returned because she was afraid to face that cowardice. Ukitake was struck by his illness at that moment, and the Hollow-Kaien attacked her again. Ukitake yelled at her to kill it because it wasn’t Kaien anymore. She stabbed him through the heart. In the manga, Rukia stabs Kaien as he leaps at her, while in the anime, he appears to fall on her sword (which she is holding upright, rather than at her side in the manga). Kaien’s consciousness surfaced before he died and he thanked Ukitake for letting him fight alone. He thanked Rukia, and then apologized to her.

She took Kaien’s body back to the Shiba house to give to Kukaku and Ganju. From that stemmed Ganju’s absolute hatred of all Shinigami. Ukitake went to the Shiba house to explain to Kuukaku what had happened, and she accepted it and decided to forgive Rukia if she apologized. It took Rukia many years to work up the courage to do so. Kukaku and Ganju still make many of their own decisions based on what their brother would have done. That’s why Kukaku agreed to help the Ichigo and Yoruichi. It’s also why Ganju eventually came around to helping them.

Since his death, the 13th Division has not assigned another Lieutenant, and instead is run by two 3rd Seats, Sentarō Kotsubaki and Kiyone Kotetsu. At some point, the Shiba clan fell from its status as a noble clan for an unspecified later.

It is later revealed that due to the Hollow's special ability, Kaien and the Hollow were taken to the Hueco Mundo, where the Arrancar Aaroniero Arruruerie ate them both and took both their abilities.

Hueco Mundo arc
After Rukia separated from her companions she encountered the Arrancar Aaroniero Arruruerie, who upon removing his mask is immediately recognized by Rukia as Kaien. The two have a long chat but after he attacks her she begins to doubt him being Kaien. It is not until he asks her to kill her friends that Rukia realizes that he cannot be who he claims, and she begins to attack Aaroniero. Rukia learns that he has Kaien's memories, though, and that Aaroniero had absorbed Metastacia, and Kaien's spirit body along with it, and is unable to fight him. After recalling Kaien's teachings about the heart and using a technique that he did not remember teaching her, Rukia was finally able to bring peace to Kaien's soul.

Powers & Abilities
Genius Intellect: Kaien was a child prodigy when he was younger. Though he is modest about the level of intellect and skill he possesses. He received high marks and had in an innate aptitude in the Shinigami Academy, having graduated top of his class in two years and became lieutenant only a year after joining the 13th division.

Expert Swordsmanship Specialist: Kaien was a skilled swordsman, evident from when he trained Rukia, and somewhat shown by Aaroniero when he was fighting Rukia based on Kaien's memories.

Flash Step Expert: Kaien has shown able to effectively use flash steps, which he did to cut off a couple of Metastacia's arms, taking the Hollow by surprise.

Kidō Expert: Even when disarmed in combat, Kaien has shown that he could still fight via the use of Kidō. He was seen using fairly high-level kidō in rapid usage without incantation while still being effective.

High Spiritual Energy: According to Ganju, even by the standards of the Noble Clans, Kaien naturally had high spiritual energy. By the time he entered the Shinigami Academy, his spiritual energy was already comparable to a lieutenant.

Zanpakutō



 * Shikai: Its Shikai command is . Nejibana's shikai is represented as a cross between a trident and a ji (a Chinese halberd) with a crystalline appearance that has the ability to manipulate water. Like the ji, it bears a horsehair tassel, although it is blue instead of the traditional red; similarly the two side blades are straight with concave edges as opposed to the usual crescent blade.


 * Shikai Special Ability: Nejibana's ability consists in use the shockwaves, it creates in conjunction with trident attacks to "crush and split the enemy in two." Kaien's techniques and form are also revealed during the battle, and are described by Rukia as "a trident technique reminiscent of dancing."


 * Bankai: Not Achieved

Trivia

 * Because of their strong resemblance to each other, many fans even assumed that Ichigo was Kaien's reincarnation or at the very least his cousin until the Hueco Mundo arc.