Sama-D is from a world that he cannot remember the name of. His people were not unlike the people of Zenn-La, peaceful and technological. His planet was attacked by a swarm of spaceships that were simply testing their weapons systems. Sama-D was the last remaining member of his race.
He left his planet and drifted in space for centuries in sorrow. He then experienced a revelation that regenerated him, and he thus changed his perception of self and reality.
Six or seven hundred years he met the Silver Surfer in the Macroverse. He was able to enter the consciousness of the Surfer and become someone the Surfer would like. He appeared human and knew things of Earth. He is quite a comedian, or at least tries to be. He showed the Surfer the terminal point of the Macroverse, the only way out. But to enter meant being erased from existence. The Surfer tried and failed.
The next time he met the Surfer, the Surfer wished to try to escape once again. Sama-D was not interested in leaving but told the Surfer to send him a postcard.