Legend Lore: Koschey the Deathless; Bane of Ivan Cinder

Koschey is one of Tiamat’s Chosen; Five Ancient Dragons, raised from birth to be the supreme Archdragon under the clawed heel of her rule over Avernus. Koschey inherited the role of Archdragon after a gruesome upbringing, killing and eating dragon hearts of his siblings, gaining their strength and thus increasing his own life span.
As the centuries went on, Koschey continued to hunt others dragons for work as well as pleasure; carving out a niche for himself in the Nine Hells. It is theorised amongst the denizens of Hell that Koschey has consumed and slaughtered so much that he may never reach a natural death of old age.
Koschey's only rival is that of Ivan Cinder; who he is titled against. Ivan, legendary Adventurer of a distant world, travels into the Nine Hells from time to time on a violent crusade against the forces of Evil. Time and time again, he is torn limb from limb by Koschey, but manages to find a way to come back every time. The Wyrm Scholars of Avernus was founded to research a solution to keep Ivan slain permanently.