The main heroine Hatsunegaoka Yui from the eroge Honoo no Haramase Oppai ★ Ero Appli Gakuen

Affiliation: Ichisakura Academy second year, swimming club
Childhood friend of the protagonist. A coolheaded and mature young woman.
Although she excels both in academics and physical activities, she is naive to the ways of love and relationships in general.
Therefore, although she and the protagonist are best friends, Yui has trouble telling him what's on her mind. This is likely because of her strict family.
She is also quick to overreact to things, but apologizes when she's in the wrong.
Aside from the swim team, Yui is also in the "Black Pantyhose Lovers Club". However, the protagonist kind of just made her part of it. She didn't really want to be in it.

She is the only heroine to have an ending of her own.