Vulcan is a major villain from the X-Men franchise and is the legendary missing Summers' sibling (related to Cyclops and Havoc) - unlike his brothers he was raised away from Earth by the Shi'ar Empire and became infinitely more powerful than either of them, by the time he confronted the X-Men he had evolved into what Marvel terms an Omega-level mutant (which basically means Vulcan is capable of near-infinite power should he so desire and could even surpass physical form).