The Neo is ?.
Sometime in the course of human evolution a side-branch emerged who called themselves the Neo. They were happy with their solitary life in their community which initially prospered, until tragedy struck. Due to the actions of the High Evolutionary temporarily "turning off" the mutant gene to transform all mutants into "baseline" humans, many of the Neo perished. Among the deceased was the daughter of their leader Domina, who could breathe underwater and drowned when her powers were removed. Domina and other Neo who survived swore vengeance (misguidedly) on the X-Men and Mister Sinister (who Domina has "killed" on several occasions), with those leaving their home to exact their revenge now calling themselves the Warclan.
They first tracked down Nightcrawler, who was on leave from the team to pursue religious matters. They found him studying to be a priest and Rax hastily tried to kill him. Nightcrawler was able to save his life, but was seriously wounded and teleported off to find help in the form of Doctor Cecilia Reyes who had a clinic nearby. Jaeger, as the leader of the Warclan, demanded that it was his right to make the kill and traveled off alone to find his prey. He hunts down Nightcrawler but is surprisingly defeated by Cecilia who, in a panic, turned her force field into a spiky barrier which impaled the ruthless man. The rest of the clan sensed Jaeger's death and this only infuriated Domina more. Rax took over as the new Jaeger.
Meanwhile in space, the X-Men attempted to help repair a space station as an act of good will. Among the X-Men present was Shadowcat, who found herself attracted to a worker, named Seth. He actually turned out to be a spy planted by the Neo, and he sabotaged the space station and kidnapped Shadowcat, believing her to be of Neo heritage. The X-Men barely survived the encounter.
Running from the Warclan, Nightcrawler and Cecilia happened upon Detective Charlotte Jones —a longtime ally of the X-Men. She wa hunting down a sociopath named Rufus Delgado and accompanied the two X-Men on their journey. Cecilia saw several vials of a mutant performance enhancing drug called Rave and —being a good doctor— she picked them up so that no one else would be hurt by it. They got separated and all became trapped. Charlotte Jones, Delgado, and Archangel (who decided to help out his friend) became caught in the illusionary thralls of the two younger Neo, Elysia and Tartarus, while Cecila and Nightcrawler had to face off against the warriors of the clan in the basement of an abandoned apartment complex. Nightcrawler passed out from his injuries leaving Cecilia to defend herself and her friend. While facing off against the immense mutant Anteus she decided to take the Rave to better her chances of survival. The drug worked and she defeated the giant, but then had to fend off the barrage from Salvo's attack. The X-Men finally arrived to help but were quickly defeated by Domina who adeptly used the collective powers of her Warclan to best them. She then ordered Barbican to seal off the building and the X-Men left so as not to be trapped inside. However, Cecilia volunteered to stay behind since Charlotte Jones was still trapped as well.
Trapped inside of the illusions of Tartarus, Charlotte Jones and Delgado were in reality merged into a gestalt being with Delgado being the dominant form, and they went about the building hunting the Neo. However, Rax approached the being with the proposition of an alliance to side with him against Domina for the leadership of the group. Cecilia managed to evade capture by the Neo for a week and stumbled upon the Charlotte-Delgado being. Wolverine and Nightcrawler teleported inside of the sealed complex just in time to save Elysia from being attacked by the creature. They were able to convince the girl that the X-Men had nothing to do with the worldwide power loss and tried to get her to talk to Domina.
Rax has his fellow Neo Junction teleported him outside of the complex so he could fight Rogue. He defeated her (or so he thought) and offered her the same alliance against Domina. Rogue accepted but confided in her teammates that she didn't trust Rax. Under his orders, Barbican opened the complex for the X-Men who had to fight the combined might of the Neo. However, their battle was interrupted by the Delgado creature and the X-Men helped to stop it. After the threat was dealt with, Elysia convinced Domina to let the X-Men go, which she complied to. As the X-Men left, the building was sealed off again.
Trying to prove himself to the clan, Rax once again ventured out on his own to try to kill Gambit. Rax had to revert to unethical conduct (endangering the lives of civilians) in order to win the fight. But just as the Neo arrived and ordered him to kill his target, the New Orleans Thieves Guild (Gambit's family) also showed up. Domina decided to allow Gambit to live and they went back to their base.
Shortly after, Magneto arrived at the Neo's fortress and commands them to serve him in his Genoshan army. The Neo resist and for their efforts Magneto dismembers Rax and Salvo. Having proven himself to the clan, Domina bows before her new leader. Given that most of the Neo were never seen from again, it can be inferred that many of them perished along with millions of other mutants when Cassandra Nova sent her wild Sentinels to attack the island, however they seems to have (for many of them) survived.
The X-Men encountered another group of Neo known as the Lost Souls. The renegade Neo Ransome Sole was also met, with him having ties to both Domina and Elias Bogan.
M-Day and Extinction
On M-Day, the Neo were as affected by the Decimation as the other mutants. A few Neo (at least eight of them, and among them at least two powered) from the Warclan even attacked San Francisco after the mutant community relocated there.
When they heard about a new baby mutant, the Guardian Clan, powered Neo, came to threaten the remaining mutants on Utopia, looking for a response about the massive depoweration of their kind, and the way to revert it as mutants were about to do.
Showing up, they put their entire species in the fate of extinction: Because of this aggression on Utopia, the Evolutionaries, protectors of both Evolution and Mutants, quickly arrived, extinguishing Neo everywhere around the globe to ensure the survival of Homo superior.
No surviving Neo has been seen since. Kitty Pryde, who was suspected of being a Neo, was not affected by the termination. It is unknown if this was due to the fact she was maybe a "classic" mutant, she was at this point stuck in her intangible form, or her clear affiliation at the X-Men's side made her be spared from the Evolutionaries' action.
- Ransome Sole