UNCANNY X MEN (1981) #384
Introducing a major new enemy for the X-Men: The conqueror known as Killion! Still in Moscow, the team desperately attempts to pry information from their prisoner, the extra-terrestrial Slaver, but the price of this knowledge may spell doom for Cable and Phoenix! Meanwhile, a team of hard-bitten mercenaries are on their way to Slaver's rescue?with orders to eliminate anything that stands in their way! And all this action leads to the first official meeting between the two major X-teams in X-MEN #104!