Akharin

Akharin was a Human born in 3834 BC in Mesopotamia, on Earth.

He grew up as a soldier, a bully, and in his own words "a fool". During an ancient battle, Akharin was slain after being pierced through the heart. However, after his injury didn't kill him, Akharin came to the realization that he was immortal due to some unknown Earth phenomenon which caused instant tissue regeneration coupled with a perfect form of biological renewal.

Upon this realization, he went on to better his life, and would continue to live for another six thousand years under a number of aliases, sometimes playing a role in Human history, before ultimately taking the name of Flint. (TOS: "Requiem for Methuselah")