BIOGRAPHY - Page 2
When Magneto established a haven for mutants in space known as Avalon, he sent his Acolyte Exodus to meet with the Brotherhood to extend an invitation for certain members. St. John was one of the members not invited, as in Exodus’ words Pyro was “tainted.” [X-Men Unlimited (1st series) #2]
Soon after, St. John learned the “taint” within him was the Legacy virus, a deadly disease that targeted mutants. Knowing he was dying, Pyro travelled to a newly-established safe haven for Legacy afflicted mutants, accompanied by the Brotherhood. The haven, called Empyrean, was established by Jonathan Chambers, a mutant with the ability to suppress mutant bio energy signatures, through which he could ease Pyro’s pain.
The Brotherhood’s presence on Empyrean drew the attention of both Project Wideawake and the X-Men. Pyro’s former teammates, Avalanche and Commando, now agents of Project Wideawake, were sent in to interact with the Brotherhood and learn more about Empyrean. St. John’s reunion with Avalanche was tense but they soon reached an understanding.
When the X-Men arrived, they understandably fought with the Brotherhood, up until Pyro revealed his Legacy infection. 
The X-Men tried to warn Pyro and the Brotherhood that Chambers' abilities made him an energy vampire. Rather than having purely altruistic motives, he was using Pyro to feed his own energy supply and use as a lab rat for his experiments. Pyro countered that he was using Chambers too, to ward off the attacks caused by the Legacy virus. Further, if he wanted to turn his body over to science for testing in hopes for a cure, that was his decision to make. The debate ended when the X-Man Revanche revealed her own Legacy infection and insisted the X-Men respect Pyro's wishes for how he wanted to die. [X-Men Annual (2nd series) #2]
Later, Chambers was defeated by the X-Men and presumably Pyro left Empyrean. Striking out on his own, St. John took a job to burn down a warehouse in New York, destroying evidence of a murder. He took the job because he fully expected to die soon and wanted to go down fighting. Using his flame creatures to attract Daredevil, the Aussie fought the “Man Without Fear,” either to take the hero out with him, or to have a reputable witness to his death. Neither occurred, however, as during the fight a collapsing walkway knocked Pyro into the river, where he escaped. [Daredevil (1st series) 355]
Weakened and dying, Pyro reunited with his Brotherhood comrades, who tried to pressure him into an act of assassination. It was implied the target was Senator Robert Kelly. Pyro’s teammates thought Pyro had nothing to lose, given that he was dying, but with so little time left for him, St. John realized he didn’t want to kill anymore and wanted to go out with dignity. Leaving the Brotherhood, St. John attended a church to take confession. Unfortunately, his powers flared out of control and he set the church on fire, prompting the X-Men to respond. Incapacitated by the X-Men, Pyro tried to tell the X-Men about what the Brotherhood wanted. However, before he could do so, he was swallowed by the earth, seemingly killed by his old friend Avalanche. [Uncanny X-Men (1st series) #338]
In fact, Avalanche had faked his teammate’s death at the behest of Mystique, who had requested Pyro's aid in a seemingly sinister plan. While it appeared to everyone else that the pair were embroiled in a plot 
to assassinate Mystique’s son and anti-mutant presidential candidate Graydon Creed, they were in fact trying to save him. Ironically, X-Factor foiled their plan, resulting in Creed’s murder. [X-Factor (1st series) #129-130]
St. John must have either been released by X-Factor or escaped, as he soon went on to rob a bank and wound up shot in the process. His hope had been to gather enough money to pay a scientist claiming he could remove Pyro’s X-gene, which they believed would therefore cure his Legacy virus affliction. Instead, Pyro ended up in the hospital under police guard with his powers flaring out of control. The X-Men’s Dr. Cecelia Reyes was forced to treat him without anesthesia, as his flame would ignite the gas or melt needles. Later, he manipulated Dr. Reyes into loosening his restraints and he used the opportunity to escape. [Uncanny X-Men (1st series) #351]
Becoming desperate for a cure, Pyro was recruited by Exodus, leader of the Acolytes. Exodus promised him and a group of other Legacy afflicted mutants a cure if they would capture the High Evolutionary for him and retrieve the powerful Isotope E. In a period of remission from the virus's effects, Pyro led a strikeforce of infected mutants, which included his old friend Avalanche, to abduct and torture the Knights of Wundagore for information. Later, Exodus himself located the Evolutionary and sent Pyro’s group and some Acolytes to capture him. After an intense battle, St. John managed to capture the High Evolutionary himself, but was promptly defeated by Quicksilver. Failing in their mission, the Acolytes abandoned Pyro and his team in the Savage Land and Pyro's hunt for a cure reached another dead end. [Quicksilver #6-9]
Somehow, perhaps with the aid of his friends in the Brotherhood, Pyro made it back to the United States. In the last stages of his disease and ravaged with pain, St. John found himself stalked by a mysterious machine and sought out Charles Xavier. As the robot itself was also hunting Xavier, it was likely manipulating Allerdyce into finding the man for it. Maddened with pain and starting numerous fires across the Midwest during his flight from the robot, Pyro drew the attention of S.H.I.E.L.D. and the X-Men. He surprised the X-Men by faring well against the entire team, often not even registering their presence. Likely as a side effect of the Legacy virus, the X-Men noted Pyro’s flames had never been hotter. Despite this, the X-Men managed to eventually take him down and he was handed over to S.H.I.E.L.D. custody. Adding insult to injury, though, the robot hunting him escaped. [Uncanny X-Men (1st series) #362]
When Pyro was next seen, for whatever reason, he was a free man again. Though no longer associated with the Brotherhood, Pyro nonetheless caught wind his former team’s latest plot to assassinate Senator Robert Kelly, now a presidential candidate. Realizing he did not wish to see the man die, Pyro travelled to Boston, where the attack on the Senator was to take place, and waited in the wings in disguise until his old friends launched their attack. Though once again the X-Men intervened, this time they found themselves caught in the illusions of the female Mastermind. It was only when St. John revealed 
himself that Mastermind’s illusion was dispelled. Still, the revelation almost came too late and the Brotherhood member Post would have delivered the killing blow against the Senator, if not for the intervention of Pyro, who unleashed a massive fiery blast, killing Post and saving Kelly’s life. Unfortunately this strain finally took its toll on St. John and, as he lay dying, he made an impassioned plea to Senator Kelly to put an end to the hatred and death. His words and actions seemed to have an impact, as Kelly promised to do just that. Pyro died thanking Kelly, who indeed kept his word. [Cable (1st series) #87]
Years later, St. John’s eternal rest was disturbed when Selene infected his deceased corpse with the transmode virus and he was resurrected. Along with a horde of other resurrected mutants, Pyro attacked the X-Men for Selene and enjoyed every minute of it. However, when Selene was defeated by X-Force, Pyro and the other resurrected mutants returned to death. [Necrosha crossover]