Ghosts

From Srafopedia

When a being dies, he or she neither disappears, nor is judged and assigned to Heaven or Hell. Instead, all the Dead become ghosts (except for a very few who become Angels), who make their way to the World of the Dead, where they will remain for all time. Fortunately, Will and Lyra cut a window out of the Land of the Dead into the Mulefa World. Ghosts who leave the World of the Dead dissolve into tiny particles.