Though the origin of the zombies remains mostly unclear, various incidents leading up to the creation of the zombies can be found via radio messages found in various maps. It would appear that element 115 an element (Unepetanium) found in meteors and known to power wonder weapons, can reanimate dead cells. A meteor containing 115 is shown in the maps Shi no Numa outside one of the swamp areas. Meteor fragments can be seen on Kino der Toten, and Sangri-la. Meteors can also be seen on the moon whenever it is visible.