Elric is an albino and so sickly and ill that without drugs or magic he'd just fall over and die. Elric is the last in a long line of Emperors of Melnibone, a once-mighty empire that used to rule the world but now controls only a tiny island and is in a pitiful and irreversible decline. The Melniboneans are non-human race (closest in terms of appearance to AD&D elves, though their culture is *much* different) who command incredible sorceries, and Elric is the greatest sorceor Melnibone has produced in a long time.
In order to thwart the evil plans of his cousin and foe, Yyrkoon, Elric is forced to take up the sword Stormbringer. Stormbringer is a black, runecarved two-handed sword. It can drain the souls of those it kills; it feeds on that energy and transfers some of that power on to its master - the end result being that the more Elric kills, the more dangerous he gets. Stormbringer has a lot of nasty suprises built into it that I won't reveal here, but one that Elric learns very quickly is that it has a habit of killing friends, lovers, or other people he had no intention of killing, if he doesn't keep a tight reign on it.
Elric wears the Ring of Kings, set with the legendary Actorios stone. It is a sign of his people's pact with the Lords of Chaos and other powerful supernatural beings. Showing the ring to summoned and conjured creatures or even gods often allows Elric to command them or at least pass them in safety, because of ancient covenants his people have made with them in the past. It's an invaluable tool in his summonings.
Unlike all of his amoral kinsman, Elric is concerned with questions of philosophy and morality, and often tries to do "the right thing". However, he is by nature fierce, cruel and vengeful. When he has marked someone as an enemy, that person is likely going to die in a lot of pain, over a long period of time... when he's marked someone as a friend, they're probably in even worse trouble, because Elric is a sort of walking tragedy magnet; anything that can go catastrophically wrong around him probably will, especially if it's something that will hurt someone else he cares about.