Mizuho Asano

is the older sister of Keigo Asano. She is the 24th student body president of her grade at Kuuza Daiichi High School and evidently works to handle multiple school affairs, including the local Kendo Club.

Personality
She likes guys with shaved heads, which is why she shows a strong affection towards Ikkaku Madarame, tending to refer to him as Darling and allowing him and Yumichika Ayasegawa to stay in the Asano family's house. Mizuho possesses an exceedingly violent and bossy nature, as seen by the way she reacts to even the slightest of comments as well as the treatment of her brother Keigo.

Bount arc
Mizuho is briefly mentioned by her brother in the Bount arc. In the moments prior to his attack by Bitto, he is seen walking down the street with a bag, complaining that she forced him to return unwanted CDs to a store. Her forcing him to run the errand being the reason he was out when he was attacked.

Arrancar arc
In the anime, she is often involving Ikkaku in many comic situations. During a kendo tournament, she forces Ikkaku to participate, only for it to end before he gets to fight, leading to a non-fatal massacre of both sides just to get back at her ex who dumped her. It is believed that she is asleep within the true Karakura Town in its temporary location in Rukongai.

In [http://bleach.wikia.com/wiki/Cry_of_the_Soul%3F_The_Rug_Shinigami_is_Born! a stand alone anime-exclusive episode], Ikkaku and Yumichika stay at her place again while they are hunting an escaped experiment. During the time, she demonstrates that she's willing to throw him out for having hair. However, both characters experience development as she learns to overlook this when he saves her, and he looks on her more kindly.