岡野 真奈

The youngest sister of the Okano family.

She's a late blooming girl who dislikes Ryouta for suddenly living with her family. She is somewhat ambivalent towards him. She is naturally shy and reserved.

She is a rather serious and firm person in the family, but she has an extremely bad sleeping habit.

Her birthday is a month earlier than Ryouta's. Deep down, Mana is probably the most pleased with Ryouta's arrival because it means she can get rid of her status as the youngest child.

From official site.