After Stryker killed his family, he started a mission to rid the world of all mutants. Stryker knew he could not do this task on his own, so he traveled around and recruited many mutant hating people to join his mission. Stryker was later stopped and sent to prison, but his followers, now called the Purifiers, kept on going.
William Stryker later came back as a major player right at the start of M-Day, following the House of Mevent. Deeming the sudden massive reduction in number of the mutant population a sign of God, saying "He made the first step and now we have to take the next", basically rallying for genocide on TV. After many mortal attacks. Finally he attacked the institute with his Purifiers, killing Quill, leaving others critically wounded, and hurting Bishop, Emma Frost and other students. After Stryker's Purifiers were defeated, he was killed by the enraged boyfriend of Wallflower, Elixir. The Purifiers would later manage to acquire Stryker's remains from the authorities.
The Purifiers attempted the kill the first mutant baby born after M-Day. They attacked the Marauders in Cooperstown, Alaska but failed to kill the baby. After being infiltrated by Rictor, the group was attacked by the New X-Men, who were seeking to prove their worth to the X-Men. With the assistance of the Reavers, the New X-Men were nearly massacred, barely escaping.
Following those events, they managed to find and resurrect Bastion, who then harvested the remains of Magus and injected his remains into several living and dead known mutant killers. These people were then made into an inner circle of leadership for the Purifiers. Meanwhile, the Purifiers used a brainwashed Wolfsbane to attack Angel and obtain his wings, which, even though they appeared to be fully organic, were still composed of Apocalypse's techno-organic strain. Using the sample, the Purifiers employed a scientist named Adam Harkins to duplicate the strain and use it to create an elite team of Purifiers called "the Choir". After learning that Bastion was planning to remove Risman from the group's leadership, Risman led the Choir against Bastion's Purifiers in an attempt to destroy Bastion and the reanimated remains of Stryker, considering them unholy. Archangel later attacked the Purifiers in an attempt to reclaim the wings that were stolen from him, killing every member of the Choir. During that point, Matthew Risman was shot in the head by X-23 around the point where Matthew tried to kill Bastion.
- Rictor - Requested by Cyclops to work as spy since he was later depowered.
- Taylor - Expelled for the infiltration of Rictor.
- Nimord- Blasted out of the timestream.
- Father Matthew Risman (second leader) - He was scarred by Dust and later shot in the head by X-23. He was regarded as Stryker´s sucessor and thus leader of the organization.
- Reverend Craig - Mauled to death and eaten.
- Eli Bard - Left the Purifiers after getting himself infected by the transmode virus.
- Leper Queen - Shot and killed by X-23.
- Adam Harkins - A member of the Facility who is the creator of the Choir.
- Gabriel - Leader of The Choir. He was killed by Archangel along with his whole team.
- Colonel William Stryker - Founder and first leader. Killed by Elixir and reanimated by Bastion. Currently deceased.
- Donald Pierce - Destroyed by an optic blast from Cyclops.
- Bolivar Trask - Killed himself after escaping from Bastion's control.
- Graydon Creed - Killed during the final battle.
- Stephen Lang - Killed during the final battle.
- Bastion - Returned to life by the Purifiers. Ultimately destroyed by Hope Summers during the final battle of Second Coming. He was at this time the organization´s supreme leader.
Along with those there are many more, because William Stryker searched the globe in search of mutant hating people, coming thousands to join his "noble" cause.