Koshiro Saeki

Koshiro Saeki (佐伯 耕四郎 Saeki Kōshirō) is a 27-year old largely-built man usually sporting a five o'clock shadow who works for a marriage-arranging company and lives with his father. He had almost completely forgotten that he had a sister until she came and moved in with them. He finds himself battling with society's definition of what an older brother should be and his sexual and romantic feelings for his sister.