Yakuza Girl
ヤクザガール ～ブレイド仕掛けの花嫁～
A young boy named Senguu Fumihiro enrolls in an elite school to fulfill a promise to his dying grandmother: to find a suitable wife. On his first day, the students start attacking one another, and one transforms into a monster. During the chaos, he is rescued by a girl named Akari, who is assigned to protect him by one of the groups that control the school.