Sei's Onee-sama is not given a name, but appears in flashbacks. She apparently chose Sei because of she liked the latter's beautiful face (she said she chose Sei for her face so as to not give the latter any pressure or expectations). She does not pressure Sei to find a petite sœur, nor coerce her into making Shiori into one; rather, she tells Sei to choose her own path without any regrets. In the third novel, Sei describes her as someone who is noble enough to be worthy of the Gigantea title; she really does, care for Sei, as shown after Shiori leaves. Sei began to depend on her a lot after this too. She graduated from Lillian wishing Sei to find a good petite sœur.   (Source: Wikipedia) 

At Lillian Girls’ Academy, a renowned all-girls Catholic school, pairs of girls become soeurs, or “sisters”, in order to support and guide each other during their time at school. The shy Yumi Fukuzawa thought she was far too ordinary to attract a soeur as popular and beautiful as Sachiko Ogasawara, but for some reason, Sachiko has set her sights on Yumi — but why does she want to become Yumi’s soeur, anyway, and just what will become Sachiko’s soeur entail? 
 
(Source: Maiden Japan)

__Birth Name:__ Izumi Arai (新井泉)

[Profile (81 Produce)](https://www.81produce.co.jp/actor_search/index.php/item?id=237) | [Official blog](https://ameblo.jp/number-373/)

The female half of the musical duo [TWO-MIX](https://anilist.co/staff/102352/).

Married mangaka [Gosho Aoyama](https://anilist.co/staff/97804/) (creator of _Detective Conan_) on her birthday, May 5, in 2005. Later divorced on December 10, 2007.

**Non-Anime Roles:**
• Fu Hua (Honkai Impact 3rd)

The second season of Maria-sama ga Miteru. 
 
The spring term is beginning for the students at Lillian Girls' Academy. Friends are reunited, but for the Yamayuri Council, it's a bittersweet time. Yoko, Eriko, and Sei are busy preparing to depart Lillian while Sachiko, Rei, and Shimako are doing their best to ensure that their dear sisters receive a memorable commencement. 
Sei's departure will leave a sizable hole in the White Roses, and filling it won't be easy. But is there anyone who could appeal to Shimako enough to become the next Rosa Gigantea en bouton? 
(Source: RightStuf)

The third season of Maria-sama ga Miteru. 
 
Summer has arrived at last, and with it comes the promise of summer break for the students of Lillian Girls’ Academy. Sachiko and Yumi retreat to the summer home of the Ogasawara family for a season of rest and relaxation, but their rosy trip soon sours when some old friends of Sachiko’s unexpectedly drop in. These wealthy snobs turn up their noses at Yumi and Sachiko’s relationship — and if Yumi isn’t careful, her blissful summer at Sachiko’s side could come to an abrupt and tearful end. 
 
(Source: Maiden Japan)

Former Rosa Gigantea