Hana yori mo Yaiba no Gotoku

The country of Japan is being terrorized by the undead, known as Revenants. Tachibana Kaguya makes it her life goal to protect her fellow citizens from these zombie-like creatures, just as her father did before her. When she enrols in Reimeikan Academy, a school that specializes in training soldiers that will eventually become part of a movement to expel the Revenants once and for all, she is reunited with Tokugawa Ichii... a boy her father had died to protect—a boy who had promised to build her a world free of monsters.