Nanako Misonoo

Nanako Misonoo is the protagonist of Oniisama E... She finds a friend in Kaoru during her first year at Seiran and is helped by the older woman more than just once. Nanako is also pulled to Kaoru through Rei Asaka who is Kaoru's best friend. The woman protects Nanako quite often and is a person the girl can rely on.

Kaoru also seems to know more about Nanako than the girl even knows herself. It is revealed later on in the series. Kaoru will make her an important disclosure: Nanako's confidant is in reality her stepbrother. Her stepfather abandoned Takehiko to marry her mother. How Kaoru knows this is defined later as well.

Rei Asaka

Rei Asaka, nicknamed Hana no Saint Juste, is an intelligent and accomplished young woman, who like Kaoru, is admired by all of the girls at Seiran Academy for her talents, behavior and looks. Kaoru is her closest friend and it is likewise the other way around. Both know deep secrets of each other's lives and support each other in their own ways.

Both are the few who can recognize the inner torments, isolations and pasts. They are very alike in terms of sides of a coin - opposite faces, but still of the same source. Kaoru is actually quite dependent on Rei and feels she is not confident enough to live alone.