Appearing in "Night of the Demon!"
- Cyclops (Scott Summers) (Main story and flashback)
- Thunderbird (John Proudstar) (Only in flashback)
- Storm (Ororo Munroe) (Main story and flashback)
- Wolverine (Logan)
- Colossus (Piotr Rasputin) (Main story and flashback)
- Nightcrawler (Kurt Wagner)
- Banshee (Sean Cassidy) (Main story and flashback)
- Professor X (Charles Xavier)
- Moira MacTaggert (First appearance)
- Kierrok (First appearance)
- Project Armageddon (First appearance)
- Count Nefaria (Only in flashback)
- Marvel Girl (Jean Grey) (Poster)
- Beast (Hank McCoy) (Poster)
- US Air Force
- Col. Michael Rossi (First appearance) (Apparent death)
- N'Daré Munroe (First appearance) (Only in flashback)
- Bolivar Trask (Mentioned)
- Larry Trask (Mentioned)
Races and Species:
- Harrier jet
- VTOL aircraft (Destruction)
Synopsis for "Night of the Demon!"
Despondent over Thunderbird's death, Cyclops lashes out with his optic blasts and unknowingly damages an ancient cairn on the grounds of Xavier’s school. As he returns to the mansion, he is unaware that his optic blast has released the demons Kierrok and the N'Garai.
Inside the X-Mansion, Professor X and Banshee observe the new X-Men undergo a Danger Room training session. In the middle of it, Nightcrawler’s teasing angers Wolverine to the point where he genuinely attacks him with his claws. Banshee ends the session and points out that had it not have been for Kurt's teleportation power, Wolverine might have killed him. Wolverine’s cavalier acknowledgment of this fact disturbs his teammates.
A short while later, Professor Xavier is expecting the school’s new housekeeper to show up. Sean, still annoyed at Wolverine, answers the doorbell when it rings. He is instantly smitten by the new housekeeper, who introduces herself as Moira MacTaggert.
Meanwhile, at a secret installation, Colonel Rossi of the U.S. Army arrives on the site of Project: Armageddon. Rossi inspects the operation and discovers that the project’s director, Stephen Lang, is obsessed with exterminating mutants. Disturbed by Lang’s zealous attitude, Rossi threatens to shut the operation down. But as Rossi attempts to leave, Lang vows that Rossi will never make it back to his superiors alive. Lang is depicted standing next to a Sentinel robot.
Back at the X-Mansion, the heroes are relaxing and getting acquainted with Moira when Cyclops is suddenly hurled through a wall. Following behind him is the demon Kierrok the Damned who has come to destroy them all. The X-Men pile on the monster, fighting together to take it down. Even Moira enters the fray, armed with a shotgun. Wolverine's adamantium claws seem to kill the demon. However, it suddenly comes back to life. A revived Cyclops explains that he had been combatting the demon for a while and each time he thought he’d killed it, the creature came back to life stronger than before. The Professor scans the creature’s mind and is bombarded with disturbing demonic images. He does manage to ascertain that the cairn which released the creature is the key to stopping it. Xavier dispatches Storm to destroys the cairn.
As her teammates continue battling Kierrok, Storm flies to the location of the cairn and is attacked by a legion of N'Garai monsters. They swarm around her and drag her towards the cairn. Realizing that they intend to drag her into it causes her to relive memories of her traumatic childhood in Cairo where she was buried alive. Panicking, Storm unleashes the full extent of her powers and strikes the cairn with a tremendous lightning bolt, utterly destroying it. With its destruction, all of the demons, including Kierrok, vanish.
Meanwhile, in the Red Hook neighborhood of Brooklyn, an aircraft carrying Michael Rossi crashes and erupts in flames. Rossi is presumed to be dead.
- From this issue onward, Wolverine assumes what had previously been established as Thunderbird's role in the team as the outspoken, hot-headed and rebellious member.
- The longtime X-Men ally Moira MacTaggert is introduced in this issue. Curiously, she is introduced as the school's housekeeper, a role that was almost immediately retconned into her being Xavier's scientific colleague.
- The cairn and the N'Garai return in Uncanny X-Men #143. Dialogue from this issue seems to indicate that Claremont initially intended the N'Garai demons to be major recurring antagonists for the new X-Men, although this was not to be.
This issue features what is arguably the first instance of Wolverine cutting loose during a fight. Controversial at the time, his willingness to go "all-out" would be a large part of his eventual popularity.
- X-Men #95 - Death of Thunderbird