Shin  

In the official Angels of Death guidebook, it is explained that while working on one of his furniture, Shin hurt his hand by accident, causing his blood to stain the furniture. Seeing the beauty in the furniture stained by his own blood, Shin used his own body as ingredients to make the furniture without a care of his own body, which resulted with his death. Deeming that the twins fit the criteria to become an angel for Grays experiment, Danny invites them. However, Gray would only accept either one of them, deeming their dependency towards each other as imperfect.Driven by the idea that only one being is perfect, each twin decided to kill the other. It is unknown which twin succeeded killing the other as the survivor reappears and reintroduces himself as the "one complete" Shin.