Karl was the son of an adventurer, and on one expedition they traveled to Tierra del Fuego near the Antarctic Circle. On the trip Karl was attacked by giant pteranodons who had migrated there from the Savage Land, and was bitten by them. He survived, but somehow his genetic structure was altered, and he started craving the life-force of living things. He needed it to survive. At first Karl kept his power a secret, but he still needed to use it in order to live, and he sapped the energy from human beings, making sure not to kill them. Later, he became a doctor and hypnotherapist, and created a device that would transfer his patients life-force to himself.