Kūkaku Shiba

is the leader of the Shiba clan. She is the sister of Ganju and late Kaien Shiba as well as a personal friend of Yoruichi Shihōin.

Appearance
Kūkaku is youthful-looking woman of average height. She has green eyes and wears bandages over her long messy black hair that parts down in half at the small of her back. She wears a white skirt and provocative red robe exposing her ample bosom. She is missing her right arm and has a tattoo on her left arm. She wears bandages around her right shoulder and both ankles. She also has wooden sandals and a cloak.

Personality
Kūkaku is violent and very aggressive, often scolding and beating those who annoy her. Kūkaku has been known to change the location and design of her house without warning. While the actual design changes, the theme is consistent and the houses are recognizable from a single glance. Yoruichi notes that she prefers to live away from built up areas, where it is quieter.

Kūkaku smokes using a pipe. Additionally, she also is respectful of her deceased brother's memory.

History
Kūkaku was educated by Koganehiko and Shiroganehiko, who continued to stay in her service after the fall of the Shiba family. After Kaien's death, Jūshirō Ukitake informed her of the events surrounding Kaien's death. Kūkaku's home used to be located close to the West Gate of Seireitei. She then moved to a location further away from the gate, and changed the design of the house to have Human hands holding a banner with her name on it.

Soul Society arc
After an unsuccessful attempt to break into Seireitei, Yoruichi leads the Ryoka to Kūkaku's house. Koganehiko brings them to the door of Kūkaku's room. Before he can introduce them, Kūkaku tells him to open the door, stating that it seems there is a rare guest. She greets Yoruichi, saying that it has been a long time since she last saw her and asks who the people with her are. Yoruichi asks for her help and explains their situation to her. Kūkaku agrees to help, saying that she cannot refuse since Urahara is involved. However, she states that while she trusts Yoruichi, her trust does not extend to her companions. She therefore decides to send Ganju with them. She opens a door to allow him in and is surprised to learn that they have already met Ganju.

Kūkaku beats the pair into submission when they start to fight and warns Ichigo that if he does not like the way she runs her household, then he should leave. She accepts his apology and instructs the group to follow her. As they walk along a corridor, Uryū Ishida notes that it is well lit considering they are underground. Kūkaku tells him that she planted light vines between the walls and ceiling. She ignores his follow-up question, instead telling Ganju to open a door and revealing the base of the chimney-like structure beside her house. Ichigo and Uryū ask what it is and she replies that she will use it to send them into Seireitei from the sky, revealing that she is a master of fireworks.

She calls for Koganehiko and Shiroganehiko to raise the platform they are standing on. The ceiling retracts and the platform ascends to just above ground level, where tells the others that it is her personal fireworks station. After she scolds Ganju again, Uryū questions whether they could survive the attempt. He is then hit on the head by a Reishūkaku, which Ichigo then catches. Kūkaku tells him to place his reiatsu into the sphere. When Ichigo asks how to do this, she tells him to focus his reiatsu on his palm as if he was using Kidō, saying that she thought all Shinigami knew how to use Kidō. Yoruichi tells her that Ichigo is not an officially trained Shinigami and thus does not know any Kidō. She tells Ganju to show him and beats the pair when they do not co-operate.

As Ganju demonstrates the cannonball formed by the Reishūkaku, Kūkaku tells them that Seireitei is surrounded by a wall of Sekkiseki which generates a special energy wave from its cut surfaces, forming a barrier above and underneath the city. As Ganju tires, she tells him to maintain the cannonball, saying that she will launch them towards the city and the cannonball will allow them to break through the barrier rather than be killed upon contact with it. She then orders them to a training area to prepare. As they leave, Ganju asks her if is she is really going to help them. Ganju states that he will not help a Shinigami, no matter what she might say to their brother. Kūkaku silences him, reminding that she told him not to bring that up ever again. She instructs him to go and not to let anyone see his "pathetic" expression. After he leaves, Kūkaku apologizes to Kaien, saying that she is going to help a Shinigami like the one that killed him. She notes that if he was alive and she did not help them, Kaien would likely scold her.

Later, Ichigo is able to activate the Reishūkaku. Kūkaku notices the pressure and tremor caused by this and rushes to investigate. She finds Ganju and asks him what happened. He apologizes to her and she opens a door to see Ichigo inside a large sphere of energy. She tells him to focus and refine his reiatsu, which he does. She then scolds and beats him when he loses concentration, causing it to explode. When the group are ready to depart, they gather at the base of the cannon. Kūkaku asks Ichigo where Ganju is, but he quickly arrives and begins to talk about Kaien. She unsuccessfully tries to silence him. When he finishes, she compliments his words and tells him not to run away during their mission. She then asks them if they are all ready.

Kūkaku asks Ganju if he was studying and if he has learnt the spell needed to control the flight of the cannonball. She states that she will use "Kakaku style version 2" and asks him if he can handle it, which he claims he can. She opens a door at the base of the cannon and orders the group to enter. Noting that it is almost dawn, she states that she will launch them when the sun rises. After launching the cannonball, she tells Ganju to take care of himself.

Several days later, Kūkaku visits Jidanbō Ikkanzaka, commenting that he has slept for five or six days straight. She invites him to go for a walk with her, saying that she wishes to see Yoruichi. Sometime later, she and Jidanbō make their way to Sōkyoku Hill after Sōsuke Aizen reveals himself as a traitor. She tells Yoruichi that she became bored and came to see how she was doing, before helping Jidanbō attack the other Gate Guardians, defeating Hikonyūtō with Kidō. After Aizen and his forces are seemingly subdued, the Menos rescue him, Gin Ichimaru, and Kaname Tōsen, and both Kūkaku and Jidanbō watch them as they depart for Hueco Mundo.

After the conflict within the Seireitei has ended, Kūkaku forces Ganju to do push-ups, saying that he was of little use in the second half of the battle. She tells him that she will make sure that he is in the frontlines from the start the next time. They are interrupted by the arrival of Rukia Kuchiki. Kūkaku asks what she wants and Ganju tries to tell her who she is, but she cuts him off, saying that she is the one who killed Kaien. Rukia apologizes, saying that she was cowardly for not doing so before. Kūkaku cuts her apology short, saying that it is too long and hits her when she tries to continue. She reveals that she heard the details from Jūshirō Ukitake and decided that she would forgive Rukia if she just said one word of apology. She subsequently invites Rukia, Ichigo and Orihime Inoue to share a meal with her household.

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

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

Equipment

 * Sword: Kūkaku possesses a sword which resembles an ordinary katana. It has an pale orange hilt and a rectangular tsuba, the corners of which curve inwards. She keeps it attached to the back of the stub of her right arm.
 * This invention uses its weilder's reiryoku in order to generate and maintain a spherical shell of energy that protects them against the barrier surrounding Soul Society.
 * A large chimney-like structure with a capped top which is located behind her house. It is a Kidō-driven device that launches the Reishūkaku into the air.

Power & Abilities
High Spiritual Power: As a member of the Shiba family, Kūkaku possesses a high level of spiritual pressure.

Kidō Expert: Kūkaku is capable of using a level 63 Hadō, with which she defeats Hikonyūtō. Kūkaku has also shown that she is able to use advanced Kidō techniques, such as "Kakaku style version 2, Kagizaki", to launch a from her, a Kidō-driven device.

Keen Intellect: Kūkaku has shown herself to be a rather insightful woman, able to quickly understand the situation at hand and act accordingly. She is a well-informed person, having good knowledge of events in Soul Society.

Enhanced Strength: Kūkaku has shown herself to be physically strong, able to simultaneously beat up both Ichigo Kurosaki and Ganju barehanded.

Fireworks Expert: Kūkaku has a knowledge of creating and using fireworks.

Trivia

 * While she is missing her right arm in the manga, the anime shows Kūkaku with a prosthetic limb.

Quotes

 * (To Yoruichi Shihōin) "Been a while since we’ve talked like this, my friend. Lucky for you, I enjoy danger."
 * (To Ichigo Kurosaki) "This is my home. If you don't like the way I run this place, you can get the hell out!"