Undead Murder Farce.

In this world, creatures like vampires and werewolves still walk about, but Aya Rindo can’t say the same for herself. This beautiful disembodied head, carried by her maid Shizuku Hasei, is a detective in search of her stolen body. One evening, they meet half-human Oni Slayer Tsugaru Shunichi, who offers a lending hand. Now, the trio is traveling through Europe, solving mysteries along the way.