|Known characters||Dee Dee|
A Spirit is the soul of a human that has passed away. Some spirits still wander around on Earth because they have an unfinished job to accomplish or if they rejected by both Heaven and Hell. In Billy's case he was rejected by both afterlife realms and spent his afterlife on Earth. Dee Dee on the other hand was still there to watch over her little brother Dexter, in the hope he would have a good life.
Spirits are able to speak directly to the Grim Reaper and sometimes are able to extend the life of a human, as shown when Dee Dee asked to let Blossom live after she drowned. Spirits are able to see undead creatures and other deceased beings.