Issues 43-53 

Quicksilver attends Xavier’s funeral at Magneto’s wrath. Quicksilver and Scarlet Witch have betrayed Magneto once already and joined the Avengers only to return after the way ‘homo sapiens’ judged them

It is revealed that Xavier had been secretly training Jean to learn how to use telepathy in addition to her telekinesis

Revealed that Magneto was controlling the bullet which grazed Scarlet Witch by a human causing them to return to him

After capturing all the X-men except for Angel, Angel flies away and stumbles on an island where he meets the Red Raven 

Red Raven is a survivor of a plane crash when he was a baby and was adopted by the Sky People who live on an island in the sky 

He was raised by them for 21 years until the Sky People decided they wanted to attack homo sapiens to which he opposed so he regrettably had then gassed the citizens into suspended animation after which he separated the legions into the military complex and isolated that section from the main island to below ocean depths where it would rise again 20 years later in the present. He must put them into SA every twenty years

The island is submerged underwater again and Angel flies off to find the Avengers 

Magneto is defeated with the help of Black Panther, Hawkeye, Wasp, and Goliath (Hank Pym)

Agent Duncan reveals Xavier’s will to the X-men which is leaving the mansion to them 

Juggernaut escapes from the Crimson Cosmos within the Crimson Gem where he was imprisoned in Issues 32/33 in Masterworks Vol. 4

Juggernaut is enraged when he finds out that Xavier is dead because he didn’t kill him

As quickly as he arrived, he is pulled back to the Crimson Cosmos 

Agent Duncan reluctantly forces the X-men to disband and go separate ways after the incident as they are too big a target together

Beast and Iceman encounter Warlock again this time masquerading as a magician called Maha Yogi. He is defeated again

Jean and Cyclops deal with a robot called Computo which is controlled by the cyborg Quasimodo

Mesmero, a disciple of Magneto, uses a psychic machine to locate and hypnotize latent mutants 

His army of Demi-Men come into conflict with the X-men

One of the mutants is named Lorna Dane

Mesmero kidnaps Lorna Dane and awakens her latent mutant ability which is magnetism. Mesmero also reveals that Lorna is the daughter of Magneto which she comes to believe 

Magneto appears who was thought dead when the X-men and Avengers defeated him

Lorna flees with Magneto due to conflicting emotions and Iceman is reprimanded by Cyclops for emotional compromise due to feelings for her and her being the daughter of their archenemy. Iceman storms off

Elsewhere in a desert, a being known as Erik the Red arrives and proclaims to be Magneto’s equal

Erik the Red attacks Magneto’s base of operations

Magneto and Lorna are there as well

Erik claims that he has come to join Magneto

Cyclops tells the X-men (save Iceman) telepathically to rendezvous to a secret location

Magneto, still weak from his confrontation with the X-men and Avengers, commands Mesmero to submit to Erik’s command to which he relents

The X-men rendezvous inside Mesmero’s HQ with Erik the Red who turns out to be Cyclops. Iceman is also there

Lorna is torn about defending her father and battling her former friends

Iceman tells her that Magneto conned her into thinking and believing he’s her real father because of their abilities

Lorna turns on her father who escapes and leaves Mesmero and the X-men for dead as the place is set to explode

Jean guides them out a they leave Mesmero for dead as well

By tampering with a device that transports living matter into radio energy and sends it into space, Jean, Cyclops, and Beast inadvertently release the FF villain Blaastaar from the Negative Zone

Blaastaar is defeated

Angel’s father Warren Worthington II is murdered by The Dazzler who is revealed to be Angel’s uncle and his father’s brother because he was going to spill about Dazzler’s plans for world conquest 

Dazzler’s plans backfire and he falls to his death after punching Warren when being carried mid-flight by when Warren can only save the former hostage Candy Southern who he was also carrying

This story most likely takes place between issues 46-49

After initially opposing Scott’s offer to join Xavier’s X-men, Iceman realizes it is for the best to join after experiencing bigotry from ‘homo sapiens’ and becomes the 2nd X-man

Hank Mccoy’s father was exposed to radiation who in turn passed it onto his son

Years later when Hank Mccoy is in college, a man called El Conquistador exploits Hank in stealing a miniaturized power plant after threatening to kill his parents

The X-men are pointed towards Hank’s location through Xavier’s firsttime use of Cerebro 

El Conquistador reneges on his promise to let his parents go after he obtains the object

Cyclops, Iceman, and Angel arrive and defeat Conquistador who unwittingly transmits electricity into his body (through Xavier’s powers) and kills himself. Hank frees his parents and becomes the 4th X-man