Apocalypse

First of the second generation of mutantkind
Abandoned at birth due to his monstrous appearance
Forced into slavery, turned on his masters & conquer all that stood in his way
Championed an extreme philosophy of mutant supremacy & "Survival of the Fittest";
Recruited by the Celestials, became a mix of organic & Celestial technology
Worshipped as a god by various cultures around the world
His children were the first Horsemen of Apocalypse
Periodically entered lengthy periods of regenerative rest to prolong his lifespan;
Awoke at various points to influence history, provoked a war between humans & mutants