The biggest and best adventures of Marvel's mighty mutants - these are the X-Men Milestones! And this event rocked not only the X-titles, but the entire Marvel Universe! For months, the force of nature known only as Onslaught has struck from the shadows - but when the X-Men discover Onslaught's startling true identity, the villain's plan kicks into high gear! Determined to punish mankind for a litany of sins, Onslaught laid siege to the X-Men, Avengers, Fantastic Four and more - kicking off a cataclysmic conflict destined to deprive a world of its most revered icons! Earth's greatest heroes face their ultimate enemy in an explosive saga that transformed the Marvel Universe! COLLECTING: UNCANNY X-MEN (1981) 333-337; X-MEN (1991) 53-57; ONSLAUGHT (1996): X-MEN, MARVEL UNIVERSE, EPILOGUE; AVENGERS (1963) 401; FANTASTIC FOUR (1961) 415; WOLVERINE (1988) 104; CABLE (1993) 35