When the Xavier Institute opened its doors to a large new influx of students, Emma Frost became one of the school’s headmasters. The students were organized into six-person squads, each with its own name; Emma’s squad was designated the Hellions, in honor of her first team of students. Their leader was Julian Keller, who shared his squad’s codename, Hellion. A powerful telekinetic and an embarrassment to his rich Beverley Hills family, the charismatic and arrogantly self-assured Keller swiftly became a favorite pupil of Frost’s. Brian Cruz had immigrated to the U.S. from Puerto Rico as a child; able to telepathically mark someone by touch so that they temporarily either repelled or attracted others, he was dubbed Tag. Santo Vaccarro’s mutation had turned him into a superstrong rockman, able to detach and fire his limbs like missiles, then reattach them later, earning him the soubriquet Rockslide. Jay Guthrie, Icarus, the younger brother of original New Mutant Cannonball, had developed wings enabling flight, a powerful healing factor, and a voice that allowed him to sing like a choir. Cessily Kincaid had transformed into living, liquid metal when her powers manifested; unable to cope with a mutant daughter, her parents sent her to Xaviers’, where she became Mercury. Sooraya Qadir was an Afghani girl who had been sold into slavery; rescued by the X-Man Wolverine, her ability to transform into a living sandstorm saw her codenamed Dust.
A rivalry immediately developed between the Hellions and the New Mutant squad, fueled by pre-existing conflicts between individual team members. Hoping to channel this rivalry productively, the teachers pitted the teams against one another in field day competitions, the first of which the Hellions won. When the F.B.I. took the New Mutant Kevin Ford (Wither), who had accidentally killed his father when his power to destroy organic matter first manifested, into custody for murder, Hellion proposed a jail break. Icarus refused to go along with the scheme, but the remaining Hellions and New Mutants leader Wind Dancer agreed. To prevent them all becoming fugitives, Icarus alerted the remaining New Mutants, resulting in a battle which was ended by the arrival of Cyclops, Frost and Wolfsbane. The charges were subsequently dropped, and Wither returned to school; but feeling betrayed by his squad, he transferred to the Hellions, with Icarus taking his place on the New Mutants. The rivalry continued through the rest of the term, with the Hellions beating the other squads to the Field Day Trophy. However, they put their rivalries aside to defeat the Blob when he attacked the school.
The Hellions went on vacation together to Julian’s home; when airport security tried to stop them boarding their plane, Julian started a fight with them before using his family connections to get his squad out of trouble. Angered at this public debacle, Julian found his parents were disinheriting him. Searching their files for evidence of financial illegalities to force them to reinstate him, Julian learned they had made their money through a deal with the “Kingmaker”. Summoning the Kingmaker themselves, the Hellions were each offered the fulfillment of one wish, in return for owing him a favor. Hellion chose to become a respected superhero; Dust to be reunited with her missing mother; Wither to be cured of his death touch; Mercury to be accepted again by her parents; Rockslide to become a successful wrestler; and Tag began training to be the next Kingmaker, so that his friends would need him. However the Kingmaker’s price was for the Hellions to steal a biological weapon for another client. The team carried out their mission, but demanded to be released from their deals, even though they knew that would cost them their wishes. Freed from their obligation, the Hellions captured the Kingmaker and handed the weapon over to the authorities before returning to Xavier’s for the new term. In the wake of M-Day, Tag was among those who lost their powers and subsequently slain in a rocket attack by anti-mutant bigots; with so many students depowered, the individual squads were disbanded, with many of the surviving members joining the new trainee X-Men team.