Interspatial rings

These rings can only be used by its user, who has to bind it with blood. When the user dies, the rings become unbound and without a user, though the things they store remain inside. Thus, killers of interspatial ring owners will have to bind it with their own blood before they can take the things inside out. There is a limit to the number or amount of things that can be stored inside an interspatial ring, as the size of the interspatial ring is limited, but there seem to be different sizes of interspatial rings (needs to be checked).