The ghosts of Greenpond come in different types depending on what happened after they died, not before. The two main ghosts are the sentinel and Mose.
Bound to Bones Edit
The sentinel was bound to his bones by the people who murdered him in 1656. He was able was animate in a three dimensional body apart from his bones via strong necromancer abilities, sourcing his magic from fae roots.
Mose died on a property cursed to hold ghosts captive, so he was always bound to the earth. However, in death, he bargained with an Authority on the Other Side to gain a three dimensional body (most of the time) to stay with his boyfriend, Delaware, and prevent Delaware from harming himself or others.