After altering reality so Mutants were the dominant race on Earth, the Scarlet Witch then changed reality once again, this time attempting to rid the world of the mutant gene. Nearly 90% of the world's mutants lost their powers overnight.
With few mutants left after M-Day, Cyclops opened the Xavier Institute to any mutant who needed refuge in that most difficult time. Sentinel Squad O*N*E was formally activated by the President and dispatched to the Xavier Institute to monitor the remaining mutants. They got into a brief quarrel with the X-Men but stopped after Emma Frost revealed the Sentinel units were piloted. The two groups then joined forces when the mutant-hating fanatical group known as the Sapien League attacked the Mansion. The Squad remained stationed outside of the Xavier Institute to monitor the status of the mutants living there.
The first few mutants to arrive were Mammomax, Erg, Peepers, and Outlaw. Shortly, the group grew to include Toad, Lorelei Travis, Johnny Dee, Sack, Fever Pitch, Jazz, Karma, Skids, Arclight, Caliban and Leech, Collective Man, Diamond Lil, Beautiful Dreamer, and Empath, among many others.
They were forced to live in tents as most of the mansion had been destroyed in the battles between the Sentinels and the Sapien League. Many, if not all residents, did not like the Sentinels guarding over them and the lack of direction. They soon named themselves the '198', in reference to the supposed total amount of remaining mutants on the planet according to Cerebra, and raised a flag with that number on it.
When the powerful mutant Mr. M arrived to the Institute, he took out a Sentinel because it had come close to stepping on a rare caterpillar. Later, Mr. M displayed his amazing powers by regrowing out Lorelei's hair. The X-Men and the O*N*E* Squad were both uncomfortable with him and were unsure how to approach the matter. When Erg attempted to leave the grounds, a battle ensued, only to be ended by Mr. M.
Some feared that they would have to stay there a long time when Valerie Cooper revealed plans to build more permanent facilities. When some demanded to leave, Cooper wouldn't allow it, but instead allowed them to go around a nearby town on the condition that they would wear electronic tags for tracking purposes. When Mammomax was ridiculed by a human he tried to attack, but his tag shocked him. The 198 were upset that the tags were capable of harming them.
Meanwhile, Jazz was trying to buy some drugs when Johnny Dee used his mutant power to strangled his small Jazz doll, choking the real Jazz to death. When the 198 learned of Jazz's death, they blamed the tags and started a riot. The situation quickly grew out of control and Mr. M and Lorelei decided to leave and invited all 198 members to join them. The Sentinels could only watch as they left.
When the Sentinels and the X-Men followed them to a nearby island, Mr. M proved himself more than a threat to both of them. When Scalphunter threatened Beast, Lorelei tried to stop him, only for him to hit her. That was when Mr. M lost it. Meanwhile, General Lazer agreed to allow Johnny Dee to deal with the threat. Johnny Dee used his Leech doll to cancel Mr. M's power. When Mr. M was down, Dee used his Magma doll to incinerate Mr. M. Later, when Lorelei and Leech watched over Mr. M's coffin, he seemed to evolve, giving the 198 hope.
Apocalypse soon came and offered the 198 salvation, to their curiosity. When Famine attacked, making all of the hungry, Apocalypse claimed his elixir could heal them. Apocalypse took down the Sentinels as they drank his elixir. But when the elixir was destroyed during the battle, Apocalypse left. The 198 continued to live at the institute for a while longer witnessing the attacks of William Stryker and the Children of the Vault.
Soon another riot broke out, this time led by Caliban and Erg. It was discovered to be distraction for Domino and Shatterstar to free the 198. Roughly half escaped with Domino on an aircraft and went to an abandoned SHIELD base. Iron Man placed Bishop in charge of finding the 198.
The X-Men concluded that if the 198 were found, there would be fatalities. The X-Men discovered where the base was, but Domino wouldn't let them in. Meanwhile, General Lazer gave Johnny Dee a sample of Cyclops' DNA, and with it they discovered where the X-Men and the 198 were located. General Lazer forced Johnny Dee to make Cyclops attack Bishop to prove that mutants were dangerous. When the 198 tried to help, he forced some 198 members to attack. Johnny Dee reached his limit, however, as he could only control one doll at a time.
When Val Cooper learned of Lazer's plan, she arrested him. However, she was too late, and he set off some weapons that would go off soon in the SHIELD base. When she interrogated him, he realized too late that Johnny had made a doll of him, and Johnny killed him. With the help of Iron Man and Ms. Marvel, the X-Men managed to get in and rescue the 198 and the weapons exploded. Leech stopped Cyclops' power from going ballistic, Johnny Dee was arrested, and the 198 were given total amnesty, to come and go wherever they choose.
Each teammates' arsenal
- 22 members of 198 (Earth-616)
- 14 appearances of 198 (Earth-616)
- 3 mentions of 198 (Earth-616)
- 2 images of 198 (Earth-616)
- Gallery of 198 (Earth-616)