Etrigan, son of the demon Belial, is summoned by the wizard Merlin, his half-brother.Unable to gain the creature's secrets, he bonds the demon with Jason Blood, a knight in King Arthur's Camelot. This renders Jason immortal, which he alternately considers either a penance or a curse.
In modern times, Jason Blood resurfaces as a prominent demonologist in Gotham City. Jason is called to the crypt of Merlin and discovers a poem that changes him into Etrigan. Unfortunately, he is followed by the long-lived Morgaine le Fey, who lusts for Merlin's secrets. That leads to Etrigan's first major battle. Over the years, Etrigan both clashes with and occasionally aids Earth's heroes, guided by his own whims and Jason's attempts to turn his infernal power to good use.
