Sumomomo Momomo: Chijou Saikyou no Yome

Koushi Inuzuka is a high school student who plans to become a public prosecutor, but his family's reputation for martial arts violence makes it difficult for him to achieve his goal. His father, a martial arts head, made a pact with a rival to marry Koushi to his daughter, Momoko Kuzuryuu, when Koushi was a baby, with the intention of creating the world's strongest martial arts clan. Momoko, a skilled martial artist with a childlike personality, appears at Koushi's high school, claiming to be his promised bride.