After the rescue, Roberto joins Karma and Psyche in pursuit of Donald Pierce. The three are joined by Wolfsbane, and after the battle by Sam Guthrie, a.k.a. Cannonball, one of Pierce's misguided mutant hirelings, despite initial reservations by the others. Professor X offers to train the five teenagers in controlling their nascent mutant powers, which they accept and thus become the founding members of the group known as the New Mutants, a group of junior X-Men. Although Professor Xavier's intentions are for them to only be students, over the course of the "New Mutants" ongoing series, they grow into superheroes, and they travel to such locations as space, Asgard, and the Amazon, as well as the past and the future. During his tenure with the New Mutants, he and Sam become best friends.