In Tite Kubo's Bleach, a wide variety of minor characters help round out the cast and add a little color, and one of them is Kukaku Shiba, a noblewoman in Soul Society.
Kukau played a supporting role in the Soul Society arc, and made a strong impression from the moment she appeared onscreen. Kukaku could have been bitter and angry, but surprisingly was not, despite the loss she suffered. She's a character made of stronger stuff than hate.
Kukaku Shiba, despite her casual appearance and wild personality, is a noblewoman from the minor house of Shiba. This puts her among the upper-class denizens of Soul Society, though the Shibas don't enjoy the same prestige as the Kuchiki and Shihoin families. Originally, there were three siblings: Kaien, the eldest brother, Kukaku, the sister and Ganju, the youngest brother. The three of them were quite close, and Kukaku was immensely proud and respectful of her big brother Kaien. Most likely, she listened carefully to tales of Kaien's exploits in Squad 13 under Captain Ukitake, until the day tragedy struck.
One night, the happy Shiba family was torn apart. Kaien was possessed by Metastacia, an experimental Hollow that Sosuke Aizen created, and Rukia Kuchiki of Squad 13 put him out of his misery by killing him. Kaien had already taught Rukia the true nature of the heart, and how it can endure beyond death, and without a doubt, Kukaku also knew this. She and Ganju grew to mistrust and avoid Soul Reapers after Kaien's death, and Ganju took Kaien's death even harder than Kukaku did. Kukaku moved the family's estate further away from the Seireitei and other developed areas, living in semi-isolation. She knew about Rukia's role in Kaien's death, though she never hated Rukia for it.
Instead, Kukaku accepted Rukia as a friend and expressly forgave her, and she was frankly getting tired of Rukia's constant apologies and negativity. Kukaku had the mental strength to move on, and she had the benefit of Kaien's lingering heart to sustain her. Kaien lived on in Rukia, Kukaku and Ganju alike, and that would suffice. This helped absolve Rukia of her lingering guilt, and that, in turn, helped her in battle with Aaroniero (who had assumed Kaien's likeness) and defeat him.
Kukaku is not a Soul Reaper, but she does possess an ordinary sword, most likely for self-defense purposes. She can also use fireworks and fight bare-handed, but her real strength lies in her kido spells and intellect. Kukaku is well-informed about events in the Soul Society, and it is possible that her good friend, Yoruichi, is the one who supplies her with most of that information. Kukaku can cast kido spells as advanced as #63, and she can time her casting so that, by the time a strengthening incantation is finished, the enemy is barely aware of her attack at all.
Kukaku sometimes fights like this, but she also uses kido for transport. She can set off an explosive kido in the chimney of her house, launching anyone inside toward any desired destination as if they were a cannonball. To protect the people launched, Kukaku often teaches them how to create a reishukaku -- a tough bubble of spirit energy -- around themselves. Ichigo himself knows the ups and downs of the Kukaku cannon.