Rangiku Matsumoto (松本 乱菊 Matsumoto Rangiku?) is the lieutenant of Squad 10. She often avoids her duties as a lieutenant so that she can go shopping or drinking with her fellow lieutenants. She usually uses her beauty, or her famously exposed cleavage and large breasts to gain attention or to manipulate others to get what she wants. Despite avoiding her responsibilities, Rangiku is very serious and thoughtful when carrying out her duties as a lieutenant and often her peers and subordinates look to her for important advice. She is also a competent and skilled fighter and is capable enough to overwhelm another strong lieutenant such as Izuru Kira or an arrancar.
Rangiku Matsumoto is able to withstand long enough to fight three strong fraccion of Tier Halibel. Rangiku has known ex-captain Gin Ichimaru since they were children. Gin found her almost mutilated before Aizen’s minions could kill her, thus saving her life. They remained quite close even after joining the Gotei 13 until Gin’s betrayal when he sided with Aizen (to protect Rangiku and take revenge against Aizen for ever hurting her, although Rangiku Matsumoto was unaware of this). Rangiku Matsumoto is shown to be the only person Gin genuinely cares for. She is shown to care for him deeply, mourning him greatly after his selfless death, as noted by Nanao Ise.
Rangiku Matsumoto persuaded Tōshirō Hitsugaya, while he was still residing in Rukongai, to join the Gotei 13 to gain control over his spiritual pressure. The two of them have grown close ever since. Although Hitsugaya always bickers about her drinking habit and laziness, she has an unwavering loyalty and devotion to him and frequently tries to get him to lighten up, despite his serious attitude. Before Hitsugaya, Rangiku also had a close relationship with her former captain, Isshin Shiba, who is just as lazy as herself. She often threw her responsibilities to Isshin, who would then retaliated to her back.
Rangiku Matsumoto’s zanpakutō is Haineko (灰猫?, literally “Ash cat”). Its guard is in the shape of a cat’s head. When released with the command “Purrl” (唸れ Unare?), the blade dissolves into ash. In combat, Matsumoto can control the movement of the ash, and cut anything it lands on by moving the hilt. The ash is also solid enough to be used as a shield to block enemy attacks. Due to her laziness, she has difficulty achieving bankai. Series creator, Tite Kubo identifies Rangiku as one of his two favorite female characters in the series, citing that he “has a lot of fun drawing her and creating stories with her.
More information can be found here: Wiki