Like all the Elders of the Universe, the Possessor's origin is lost in antiquity. What is known is that he is one of the oldest living beings in the universe, having been a member of one of the universe's races to become sentient after the Big Bang. Virtually immortal, Kamo Tharnn has spent the eons since his self- awareness engaged in the pursuit and recording of all the knowledge in the universe.
When the plot to kill Galactus failed, the he was sent through a black hole and ended up the the Magick Realm. Since he had no value to the Sinalinas like his brothers, Astronomer and Trader, he was essentially made a slave. He was able to tell them many stories from the vast knowledge he possessed. They called him Tale-er and he was protected by them. He eventually escaped with the help of his brothers and the In-Betweener. But the In-Betweener did not fulfill his end of the bargain. He refused to kill Galactus and instead sent him back to his own realm. When Possessor and the others protested, In-Betweener summoned Death and she took them to her realm. It is assumed she allowed them to return to life when In-Betweener returned to his own dimension and lost his power over her.
Eventually Tharnn founded a huge university and library on the planet Rus, and transferred the vast store of information he accumulated to a huge master computer. He then opened the doors of his academy of learning to all knowledge-seekers from anywhere in the universe.
- Possessor Kamo Tharnn is featured as a boss in the NES Silver Surfer game.