Orphaned at a young age after his brother Christopher used his mutant powers to drive their father insane while driving, causing him to lose control of the family car, Jesse Aaronson was placed in foster care. Separated from his brother, Jesse became emotionally unstable and was committed to a psychiatric institution after seeing several therapists. There his mutant nature manifested, and Jesse’s doctor saw his condition as a means to getting a book published by subjecting him to a series of cruel tests. Jesse was rescued by members of the Mutant Underground Support Engine (M.U.S.E.), who cared for Jesse’s well-being while training him as a field agent, codenamed Bedlam.
Seeking his brother, Jesse soon left M.U.S.E. and tracked down the mutant mercenary Domino, whom he believed could help him. He cut a deal with Domino, agreeing to give her the location of Ekatarina Gryaznova (the Prime Sentinel who implanted her with a neural-disruption device that shorted out her mutant powers during Operation: Zero Tolerance) in return for her aid in finding Christopher. Domino agreed, but only if Jesse took her to Gryaznova first. They broke into the Aguilar Institute, but Domino was captured. Jesse escaped and sought the help of the mutant strike team X-Force. During the subsequent rescue, Jesse used his power to free Domino of her implant’s effects. He and Domino then found Christopher leading the mutant team the New Hellions. Forced to choose between his X-Force friends and his rediscovered family, Jesse at first sided with his brother; however, after learning of Christopher’s insane plan to gain control of the dangerous Armageddon Man, Jesse joined X-Force in opposing him.
Soon after, X-Force traveled to Genosha to help former British black ops agent Pete Wisdom rescue an old friend. There Jesse received the memories of a well-trained martial arts student from a memory box created by the mutant Delphi. Later, Wisdom trained X-Force as a covert operations unit, helping Jesse increase the scope of his powers. He remained a member of the team until their apparent death in the explosion of an alien spaceship. X-Force subsequently resurfaced without Jesse, who was later captured by the Church of Humanity and crucified on the Xavier Institute grounds. Despite the X-Men’s best efforts, Jesse apparently died from his injuries.