BIOGRAPHY - Page 8
Despite the death of Jamie-Prime, one duplicate managed to survive. Locked away in a hermetically sealed vault inside Muir Island, this Jamie was discovered months after the M-Pox killed his progenitor. This only slowed his demise, however, for this Jamie was breaking down organically now that he was un-tethered from Jamie-Prime. Hank McCoy developed a serum which could reassign the status of "Prime" to a duplicate and, through an incomprehensively complicated sequence of events, a version of that duplicate ultimately took the serum and became the new Prime. [Multiple Man #1-5]
[Note: There is no chance in Hell I'm going through that limited series twice. For the details of what happened, see the Alternate Versions page.]
"New Coke" Jamie was in the process of getting to know Layla Miller and her son Davey from the previous Jamie-Prime when he was kidnapped by Legion. The unstable Omega-class mutant foresaw the coming threat of the X-Man, another Omega who had augmented his power even further using a Celestial Lifeseed. X-Man and his Horsemen of Salvation intended to impose a new world order of peace and prosperity, but only after tearing down the old order. Legion wanted to stop the X-Man, but was unable to come up with a coherent form of response. Instead, he used Jamie to produce an endless wave of duplicates, each of whom was possessed by a different personality and power set from Legion's fractured mind. The Jamie-Legions were sent out into the world to stop the early steps of X-Man's plans which Legion had foreseen with his precognition.
At each stage, however, the possessed Madri arrived too late, and only made events more confusing when they crossed paths with the X-Men. Finally, the X-Men tracked down Jamie-Prime in Kansas, tied to a chair and beaten by Legion to produce all the bodies he needed. Jamie explained the 
truth behind the scatterbrained, super-powered Madrox duplicates they had been facing. Legion himself had shown up at the X-Mansion in Central Park, and Jamie joined the X-Men in returning to confront his attacker. After they arrived, however, the Horsemen of Salvation made their debut and destroyed the mansion to prevent the X-Men from interfering with X-Man any further. [Uncanny X-Men (5th series) #1-3]
Madrox slipped off to a bar after that to clear his head while the X-Men dug themselves out of the rubble. However, Glob Herman came to find him hours later, asking him to help Legion and the younger X-Men seek out X-Man and help save the world. Multiple Man reluctantly got involved 
again, and the loose confederation were able to follow the main X-Men to Quadra Island in Canada to confront X-Man. The X-Men were in need of support against the Horsemen, and Legion was able to contain X-Man within his mind for a short time. [Uncanny X-Men (5th series) #4-6] This tactic ended up backfiring, though, as X-Man gained control of Legion from within, fusing two Omega-level mutants in an unprecedented display of power. Merged with Legion, X-Man grabbed a hold of Jamie Madrox and planned to replicate Legion prior tactics, splitting aspects of his personality among an army of bodies. The joke was on him, for this was only a duplicate of Jamie. The new Jamie-Prime had bailed on the battle earlier, leaving only a dupe to deal with the world-threatening shenanigans. [Uncanny X-Men (5th series) #9]
It seemed like a wise choice. The conflict between X-Man, Legion and the X-Men expanded to include dozens of mutant heroes, all of whom were seemingly killed and lost at the end of the fighting. Mankind moved on from the X-Men, popularizing an anti-mutant vaccine and aggressive 
mutant-hunting tactics by General Callahan and the Office of National Emergency. Jamie tried to remain in obscurity with Layla and Davey, but he was sought out several times by some of the remaining X-Men who needed his detective skills (despite this Madrox...not(?) having ever been a detective?). The precognitive Blindfold used him as a go-between when Cyclops and Wolverine were taking action solo, leading to the reformation of the X-Men, in some form. [Uncanny X-Men (5th series) #11]
Madrox developed a personal stake in mutant affairs when several of his duplicates were kidnapped by various parties for experimentation. Cyclops and Wolverine discovered a few Madri held captive by O*N*E when they stormed a facility to free Havok and the New Mutants. One of the Jamies had a bomb planted in his guts, and the explosion killed at least two Jamies and Guido, who absorbed the brunt of the blast to save the others. [Uncanny X-Men (5th series) #12] The Dark Beast from the Age of Apocalypse had also been experimenting on Multiple Men samples, and Jamie-Prime ran into the reformed X-Men at McCoy's laboratory as he searched for his missing selves. One Madrox remained as a mutilated cyborg, dying from McCoy's horrific body work. The Multiple Man was forced to absorb the dupe and experience that death inside his mind in order to learn the Dark Beast's current location. From that point on, Jamie Madrox was a member of the X-Men, joining Cyclops' crusade to defeat the outstanding threats the other X-Men left behind with their deaths. [Uncanny X-Men (5th series) #13]
The Multiple Man provided the remaining X-Men with the manpower they desperately needed. Madrox worked with Cyclops, Wolverine and the others against various targets such as the Brotherhood, the Mutant Liberation Front and the Asgardian invasion of New York. Dark Beast ended up being taken prisoner by the X-Men, forced to lend his intellect to Cyclops's crusade. One measure involved the rescued New Mutants, who were all acting as symbiotic hosts to the 
techno-organic Warlock, spread out between them. McCoy took it upon himself to come up with a solution, coaxing the Technarch out of his friends and consolidating Warlock into a Madrox duplicate, creating the symbiotically-paired Warlox. [Uncanny X-Men (5th series) #14-16, War of the Realms: Uncanny X-Men #1-3]
Madrox continued to serve with the X-Men while Warlox was put in charge of the growing list of prisoners under Harry's Hideaway, given that the new hybrid no longer slept. The increasing strain the X-Men were working under took its toll, though, and several members left to try and live separate lives in these dark new times for mutants. Unfortunately, one of the members was Rahne Sinclair, who was killed by a group of bigoted humans shortly after departing. Jamie and Layla had to reunite at yet another funeral for one of their closest friends. [Uncanny X-Men (5th series) #17]
Eventually, Emma Frost resurfaced with the ultimate solution to being hated and feared. With the help of several confederates, she constructed a new Cerebro unit that allowed her to mask the very existence of mutants from the minds of humanity. Mutants were no longer hated and feared, for humanity didn't even know they existed. However, General Callahan had shielded himself against psychic attack, and still commanded his techno-organic Sentinels. He launched an attack on the Hellfire Club to destroy Emma's equipment. Warlock had been the base material for these new Sentinels, and so Warlox tried to reabsorb the elements of his self from them. The Sentinels fought back and mortally wounded their progenitor. Warlox had linked the Sentinels to his/their mind, though, and had Hope mimic Emma's telepathy to wipe his mind before he passed on. Warlox died, but the induced amnesia meant the Sentinels no longer remembered the existence of mutants either.
However, General Callahan could still execute direct commands for the Sentinels, ordering them to attack specific targets regardless of whether they recognized mutants or not. The Sentinels kept fighting, and Cyclops and Wolverine strategized that Callahan had to be eliminated so that knowledge of mutants died with him. Jamie Madrox stepped up and produced as many duplicates as possible to body-block for Logan to get Wolverine close enough to stab. It was a killing field out among the Sentinels as one Jamie after another was mowed down. Wolverine got through and killed General Callahan, but all the Multiple Men, including Madrox Prime, died getting him there. [Uncanny X-Men (5th series) #18-22]
In the era of Krakoa, Jamie Madrox is one of a number of mutants who have been brought back to life by the collective powers of the Resurrection Five. Taking advantage of his numbers, the Multiple Man provides raw manpower and laboratory experience to Xavier PharmaXeuticals and the Hellfire Trading Company across multiple sites where they grow, cultivate, synthesize and mass-produce the Krakoan flowers into drugs for sale on the open market. [X-Force (6th series, #4, 11, Wolverine (7th series) #1] Strictly speaking, it has not been addressed exactly WHICH version or versions of Jamie Madrox have been brought back by the Resurrection Protocols. The detective, the new Prime, the pre-Legacy Virus original Prime, the Prime emperor, the Prime general, Warlox, Cortex, the X-factor, the Fallen Angel, the Nasty Boy? All of the above, or otherwise? Time will tell.