Shiba Kuukaku is an ill-tempered fireworks expert that lives on the outskirts of Soul Society and a personal friend of Yoruichi Shihōin. She is also the somewhat authoritative older sister of Ganju and Kaien Shiba.
She lives with her family in ridiculously-themed houses (which she changes in design and location regularly) on the outskirts of Soul Society. She is missing her right arm, which in the anime is replaced with a prosthetic, to which the reason of the loss of her right arm remains unknown. Kūkaku also appears to be as well endowed as Rangiku Matsumoto. She is the head of the Shiba family, which fell from the status of nobility after her brother, Kaien, died. Because they knew only that Kaien was killed by a Shinigami, both Kūkaku and Ganju are distrustful of Shinigami when first introduced. After Kaien's killer, Rukia Kuchiki, explains how he died and apologizes, the Shiba make amends. Kūkaku seems to have some kind of relationship with the Urahara Shop, knowing Yoruichi Shihōin and claiming to have worked with Kisuke Urahara in the past. She can perform high level Kidō spells, and she carries a short-bladed sword on her back but it is unknown if this is her Zanpakutō or not. She helps Ichigo Kurosaki and the gang into Soul Society to rescue Rukia during their first visit, launching them from her cannon with a Kidō spell.