Ruby on the Cake: Hitokui Majo no Bansankai

Within London dwells humanoid monsters that eat only men—Witches. In order to exterminate them, the British Secret Intelligence Service MI6 formed a unit known as RED. Ruby Blood, a young genius Witch Hunter, is a member of this unit. Off duty, she's just an ordinary, fun-loving girl who loves food, her family, and most of all, her father’s home-cooked dinners. But on Christmas Night, something happens that changes her fate entirely... An eat-or-be-eaten girl-led suspense! (Source: Manga UP!)