few hundred years later
Originally a Native American medicine man who constantly strived for more influence among his tribe, he was the quickest to learn Spanish and convert to Catholicism when explorers arrived, damning the rest of the tribe.
He was carried back to Europe as proof of a new world filled with impressionable, educable people.
Spaniards marveled at his intelligence, particularly his biblical knowledge. He became a widely respected priest, but still craved more power.
Like all good priests would, he turned to the bible for answers. Upon first glance, it provided none, but as he reread it, he became fascinated by the Abrahamic concepts of beasts and demons.
To the shock of the congregation and the clergymen, he left the church and embarked on a year-long journey to gather whatever information he could on the darkest of angels. Over time his obsession grew and his focus narrowed.
Somehow he came to learn that the wall between the earth and the detention of Samael--an angel born not of divine wisdom, but of human corruption--could be weakened by the union of the bones of a Nephilim and the skull of a behemoth.
His initial attempt was unsuccessful, but was enough to notify Samael of the existence of a follower.
In exchange for his servitude, Samael granted Iolis the gift of immortality. His body continued aging, but every time one part ceased to function, either the other parts would adapt to function without it, or it would be replaced with something less human--less likely to shut down.