A different Soul.

In this world, some people won't simply go to heaven when they die. The dead need guidance. When people get guidance, they go trough a place called spirit forest. When they pass there, the souls leave their forms and this will allow humans to see the ones dear to you that have passed. After the souls leave the forest, they will be placed in a human child to be reborn. There are of course some children that get a new soul, but the dead will be reborn. People all over the world train to help souls rest. If the dead don't get the guidance and rebirth, they will either become fiends or living dead. A fiend is creatures that lost their soul and are controlled by anger, regret or pain and make out a vicious form. A living dead aren't much different from a fiend but they are people who still have a heart and soul connected to this world and keep the form of a human. Some living dead seek a way to live again, a way to reach a limit in life, like me....