World Ender: Sekai ni Kirawareta Kimi to N-kaime

How many sacrifices can you make to save a girl? A world 30 years after humanity was trampled by suddenly appearing "Angels." Eugene, who works as part of a self-defense force "to be happy with everyone" even though his family was killed by "Angels," meets a mysterious girl named "Vishuki"... An extreme Fantasy Battle where you are not allowed to die until you obtain happiness, begins!!