NAKAIMO - My Little Sister Is Among Them!

Shougo Mikadono faces a bizarre challenge: to inherit his father's fortune, he must attend a new school and find a suitable wife. The girls at the school seem welcoming, making the task seem simple. However, a shocking revelation complicates everything. Shougo's long-lost sister is also attending the school, and he has no idea which girl she is. This throws a wrench into his plans, as he must now navigate the complexities of courtship while unknowingly searching for his sister. The series explores themes of family, identity, and the potential for romantic relationships to become morally ambiguous. Shougo must carefully choose his future bride, all while avoiding an incestuous relationship. The circumstances surrounding his sister's reveal remain a mystery.