Appearing in "Extermination: Part Four of Five"
- X-Men (Blue Team)
- Cannonball (Sam Guthrie)
- X-Men (Gold Team)
- X-Men (Red Team)
- Cable (Nathan Summers) (Past)
- Domino (Neena Thurman)
- Boom Boom (Tabitha Smith)
- Mimic (Calvin Rankin)
- Ahab (Roderick Campbell)
- Shatterstar (Gaveedra Seven) (Unconscious) (Controlled by Ahab)
- Lord / God (Yahweh) (Invoked)
- Professor X (Charles Xavier) (Painting)
- Dr. Cecilia Reyes (Mentioned)
- X-Force (Mentioned)
- Beast (Hank McCoy) (Past in stasis)
- Cable (Nathan Summers) (Mentioned) (Deceased)
- X-Men (Blue Team) (Vision)
- Apocalypse (En Sabah Nur) (Vision)
- Magneto (Max Eisenhardt) (Vision)
- X-Men (Gold Team) (Vision)
- Psylocke (Betsy Braddock) (First appearance; vision)
- Fantomex (Charlie Cluster-7) (First appearance; vision)
- Wolverine (Laura Kinney) (Vision)
- Logan (First appearance; vision)
- Gambit (Remy LeBeau) (Vision)
- Reavers (Mentioned)
- Cyclops (Scott Summers) (Mentioned) (Deceased)
- Moby Dick (Mentioned) (Topical reference)
- Captain James Hook (Mentioned) (Topical reference)
- Bloodstorm (Ororo Munroe) (Mentioned) (Deceased)
Races and Species:
- Prime Marvel Universe
- Mutant Extermination (Twenty years from now) (Vision)
- Days of Future Past (Vision)
- Inhibitor Collars
- Stealth Cyber Gear (Behind the scenes)
- Cyclops' Visor
- Techno-Organic Virus
- Magneto's Helmet (Vision)
- Shurayuki (First appearance; vision)
- X-23's Suit
- Adamantium (On Logan and X-23's claws)
- Reaver Virus (Mentioned)
- Honey Badger's Suit
- Guardians of the Galaxy & X-Men: Black Vortex (Mentioned)
Synopsis for "Extermination: Part Four of Five"
On Ahab's ship, he and his crew prepare to dive down to Searebro. Meanwhile at the Xavier Institute, Cannonball arrives with a subdued Shatterstar to find the place in chaos. The X-Men catch him up on the situation and Kitty Pryde decides to lead a team to go after Ahab.
Elsewhere, a shootout is underway at Cable's safe house as the former X-Force are trying to kill him as revenge for killing his older self. Marvel Girl attempts to break up the fight but neither side wants to talk and Cable fires back at his attackers. Taking his attacking them as evidence that he is not the "real" Cable, Warpath and Boom Boom lunge at him as Cable insists that they are forcing his hand, and Marvel Girl suddenly sends out a telekinetic attack that freezes everyone in the air. She demands that Cable tell her who he is and what he is doing, starting with why he killed his future self. Cable says he killed him because he was neglecting his duty to preserving the timeline because he had become attached to the time-displaced X-Men and allowed them to remain in the present despite knowing the risks. He elaborates that Ahab is trying to kill the young Iceman, which would create ripple effect resulting in mutant extermination. To prove his honesty, Cable removes his telepathy blocker so Marvel Girl can read his mind. She enters his mind to find a future where the X-Men are not whole and gradually lose more battles until mutantkind has been exterminated, all because the time-displaced X-Men refused to return to their own time. Marvel Girl releases the other mutants from her telekinesis and Cable further explains that he stole Mimic's wings (genetically identical to Angel's) so Angel could return to the past with his original wings and preserve the timeline.
In Searebro, the adult Jean Grey watches over Cyclops when Honey Badger reports to her that Ahab's ship is coming. Infiltrating Searebro, Ahab demands that Cyclops be handed to him and Jean order the X-Men to protect Cyclops at all costs. The two sides engage in battle and Honey Badger is turned into a Hound and forced to fight her sister X-23. Jean reports to Kitty Pryde that they are being attacked and many are being turned into Hounds, making it difficult to reach them telepathically. Jean and several other barricade themselves inside the medical bay where a brainwashed Nightcrawler teleports inside to kill Cyclops, but he is shot by a tranquilizer bullet fired by Cable, who Marvel Girl and the former X-Force have reluctantly allied themselves with. The older Jean telepathically learns of the situation from her younger self and Ahab finally breaches the room. Cyclops attacks him but Ahab impales him on his harpoon against the wall, killing him.
• The X-Men are at the end of their rope.
• If even one of the original five X-Men dies, our future is lost.
• Jean Grey and the X-Men only have one option left… and it may cost them everything.
- This issue's cover is a homage to X-Men #137.