When the New Mutants first debuted they were a fresh-faced class of teenagers in desperate need of training, but since then each member grew to be a capable fighter in their own right. With the team set to reunite soon in Jonathan Hickman and Rob Reis' New Mutants, it's worth looking back at just how far each member has come, and who is the most powerful of them all.
The Scottish Rahne Sinclair is no longer as meek or afraid of her powers as she was when she first appeared. Capable of turning into a wolf, or a half-lupine form with enhanced physical qualities, Wolfsbane's devout religious upbringing made her hesitant to embrace the power she truly had. Although she did grow more comfortable with her animal form over time, she never received a power upgrade or pushed herself to new limits like the rest of her team.
Originally the oldest of the New Mutants, Karma's guidance to the younger teenagers was almost as valuable as her ability to telepathically possess the minds of others. While such a power would seem to be immensely useful, telepaths are always a dime a dozen in the X-Men and Karma rarely stacks up favorably when compared to others like Emma Frost. Many of the other New Mutants have even demonstrated the ability to resist her control, so it's hard to give Karma an edge in comparison to her teammates.
If this were purely a list on whose powers have grown the most throughout their run in the comics, Cypher would take the gold medal. With the mutant ability to understand any language, Cypher was extremely lame when he debuted, often cowering in the corner during fights or relying on Warlock to protect him. Since then, however, Cypher has found innumerable applications for his powers: reading body language to excel at fighting, making magical incantations to teleport across dimensions, and even reading flaws in the structure of reality itself. He still has a long way to go to top the list, but Cypher deserves credit for doing so much with so little even as it is.
The original non-mutant New Mutant, Warlock is actually a member of a techno-organic alien species that absorbs an organism's lifeforce for consumption. He's an immensely powerful shapeshifter (who even once out-shapeshifted the Impossible Man) and often turns into vehicles or battle mechs for his teammates' use. The only thing holding him back is his gentle nature, and if Warlock had more of a fighter's heart he could give the top spot of the list a run for their money.
Probably the most overlooked member of the New Mutants, Magma rarely gets included in reunions or invited to join the main team. Despite that, she's one of the most powerful members, capable of creating devastating earthquakes and raising mountainous volcanoes that can destroy cities. Her lava form even gives her protection from most conventional attacks, and if an opponent can't take the heat they better get the heck away from her kitchen.
In case you hadn't heard, he's invulnerable while he's blastin'. The Southern co-leader of the group has a name about as descriptive of his powerset as it can get, but nothing could quite capture just how invulnerable Cannonball can get. He's taken Hulk, Iron Man, Namor, and Wonder Man all punching him simultaneously and survived an explosion that killed a giant space monster and threw its scales gigameters away! Cannonball just keeps getting better with his powers as time goes on, and in a straight-up brawl, it's hard to see him losing to anyone else on the list.
Since she's technically not a mutant anymore following the events of M-Day it may seem weird to give Mirage such a high spot on the list, but she earns it. Even without her powers, Mirage contends with everyone else, wielding a bow and arrow with deadly precision so well she once endured excruciating torture before escaping and headshotting a goblin...while using her toes to draw the bowstring. If you're looking for raw power beyond skill Mirage has plenty. As a Valkyrie for the Asgardian goddess of death, Hela, Mirage can call on divine forces to amp her to insane degrees whenever the situation requires.
However much the rest of the team's powers may have grown over the years, it's barely even been a contest as Magik always held the top spot. With an innate ability to transcend both space and time, Magik was awfully the cause of and solution to many of the adventures the New Mutants set out on. Over the years she only grew more powerful, fusing her soul with a demon as she became the ruler of her very own dimension while also mastering the Soulsword that is a hot contender for one of the Marvel Universe's most powerful weapons.
While there may have been times where the other New Mutants advanced to far greater power levels, such as Wolfsbane multiplying herself while in wolf-form or Mirage briefly gaining matter-manipulation, all of that pales in comparison to Magik serving as a member of the Phoenix Five and becoming nigh-omnipotent. Whether you're judging from where they started, where they've been, or where they're at now there's no doubt that Magik is the most powerful New Mutant.