Relatively little is known about the Tall Man. Once upon a time, he was a kind-hearted soul named Dr. Jebediah Morningside, an ordinary mortician who served as a medic for the Union Army during the American Civil War. Until he was experimenting with inter-dimensional travel and studying the connection between the world of the living and the realm of the dead. He does this to learn the mysteries of life and death, even to achieve immortality. After perfecting a machine that would allow him to travel between worlds, he stepped through the gateway. Upon his return he was no longer Jebediah, but the cold and evil being known to Mike Pearson and his friend Reggie as the Tall Man. It can only be speculated that while in a different dimension Jebediah's body was possessed by another intelligence, or that his physical likeness has been assumed by some otherworldly, evil entity while killing off the original man. It might also be that his experiences changed him radically. The Tall Man's purpose is to become the Lord of the Dead. He moves from town to town, first becoming the undertaker of that town and secretly removing the corpses from the graveyards and mortuaries. However, he is not content to just steal the already dead, but will soon kill the town's living population to add their numbers to his collection. The dwarf-like creatures he creates from the bodies of the dead serve him in our world, and he also transports them back to his own dimension. It is possible that he uses them as slave labor for his own world, the same way he uses his two legion of other undead minions called the Gravers and the Demon Troopers. The dwarfs were revealed to be byproducts of the process by which the Tall Man creates the Sentinel Spheres, which involves compacting the body and placing the brain into a metal casing. The Sentinels are used in his assaults against the living. So far he has not revealed any grand schemes for world conquest, and he tends to plunder only small, out-of-the-way towns; he is never shown invading large cities. And the towns he does plunder always seem to have an explanation for why the town's population is missing, such as a toxic waste spill. The Tall Man is a cold psychopathic traveler who explores worlds and knows all that is unknown while he destroys lives and commands his legion of the undead.