Mamono Shoukan de Dungeon Musou - Maou Gun to Keiyaku Shita Saikyou Boukensha

Having lost his family to the horrors of a Dungeon Outbreak, a young man named Yuki is cornered by the ultimate dungeon boss—Libel. Forced into a contract to become a [Monster Tamer], his path is set. Form pacts with all manner of monsters and conquer every dungeon in existence!.