The Vessel of Wrath, inhabited by the demon Seth Twiright.
A magical tool created by the Seth Twiright in shape of a golden key. Capable of shapeshift, it can fit any lock and take the form of several weapons, like a dagger, a sword or a bullet. Wielded by several individuals across the ages, eventually it fell in possession of Nemesis Sudou, who used it as the ultimate weapon for fullfil her goals.