Yoruichi Shihōin is the former captain of the 2nd Division as well as the former commander of the Onmitsukidō. She currently lives in Karakura Town with Kisuke Urahara, her accomplice and best friend as well as her former 3rd Seat before being promoted to 12th Division Captain 110 years ago. Although her real form is that of a woman, she debuts in Bleach as a black cat. Though currently she has no occupation, she helps in mentoring and training Ichigo Kurosaki and other characters throughout the series.
The first time Yoruichi is introduced, she is in her Black Cat form, and during this time her voice sounds like a man's voice, therefore causing Ichigo and the others to think she is a guy. When she is in her human form, she has long purple hair that she wears up in a ponytail, she has bright yellow eyes, much like that of a cat, and she has dark skin. She wears an orange jumper over her Stealth Force uniform, and black trousers.
When she was a Shinigami, her hair was short, and she wore the Punishment Force's traditional uniform, along with her captain's jacket.
Yoruichi is very intelligent, as she knows lots about the Soul Society and how it works. She also appears to be shameless as she has a tendency to appear naked infront of people (mainly Ichigo, to tease him) without a care in the world.
Yoruichi has many abilities, including being able to transform into a cat. As she was once the 2nd division's captain and commader of the punishment force, there is no question that Yoruichi has a bunch of unique powers up her sleeve, but she prefers not to battle with weapons so her Zanpakutō's name and abilities are unknown. She is, however, an expert with controlling her Spiritual Pressure, as she has created her own technique, Shunko, by being able to control it so well. She is also said to be the best user of the Flash Step, and is an expert in hand-to-hand combat.
Yoruichi was once the Captain of the 2nd Division in the Gotei 13, and also the Commander of the Punishment force, until Kisuke got blamed for the Hollowfication of the current Vizard, and was taken to Central 46 to be punished, but before this could happen, Yoruichi busted in and helped Kisuke escape to the real world.