The Uncanny X-Men
Inside Onslaught's citadel, Franklin Richards tries to wake Professor X. Joseph confronts Onslaught and frees Xavier from the villain's chest plate, but this only makes Onslaught stronger and causes a massive explosion in New York City.
Collects The Uncanny X-Men #287-337, X-Men #53-57, Onslaught: X-Men #1, Excalibur #100, Wolverine #104, Cable #35, Onslaught: Marvel #1, Onslaught #1-6, Onslaught: Epilogue #1, X-Men / Avengers: Onslaught Omnibus. The full Onslaught saga -- Professor Xs dark side manifests as a world-ending threat.
Collects X-Men #55, X-Man #19, Cable #35, X-Force #58, Wolverine #105, The Uncanny X-Men #336. The Onslaught crossover continues across all X-titles as the heroes fight back.
Collects X-Man #15-19 and material from 14 other series. The complete Onslaught saga - Xavier dark psyche merges with Magneto rage.
Collects X-Man #18-19, Cable #34-35, X-Force #57-58, and more. The X-titles converge as Onslaughts assault on the Marvel Universe escalates.