A crippled telepathic and telekinetic mutant called Xavier dreamed of a time when "normal" humans and mutants could live in peace. But he knew some mutants opposed this idea. So he decided to form a mutant super hero team. He had the somewhat tragic Cyclops a.k.a Scott Summer (who shoots force beams from his eyes); the winged Angel a.k.a Warren Worthington the 3rd; the smart, agile Beast a.k.a Henry McCoy (in human form); the hot shot Ice Man a.k.a Bobby Drake (turns moisture into ice) and the also the telepathic and telekinetic Marvel Girl a.k.a Jean Grey (later known as the Phoenix). Their main foe was Magneto (a mutant with magnetic powers). However they also fought the hypnotic Mesmro, the teleporting Vashiner, the Brother Hood of Evil Mutants (the members were the telepathic Mastermind, the super fast Quicksilver, the jumpy Toad and the magic-like Scarlet Witch) and flying / fire shooting mutant Sunfire. Soon the Beast drank a chemical turning him into a fur ape-man-thing. Xavier died while stopping the mad Gortesk, only it was later revealed that a shape shifting mutant known as Changeling was actually the one who died.
X-Men Ultimate Guide