Darwin worked as a taxi driver. While in this capacity, Charles and Erik asked him to join their CIA-sponsored mutant group. Darwin met his teammates, displayed his powers, and partied with them.
Following the Hellfire Club's assault on the Division X facility, Sebastian Shaw attempted to recruit the young mutants into his ranks. Angel Salvadore joined in while Alex and Darwin tried to stop her. It was during this attempt that Shaw absorbed Alex's energy blast and placed it within Darwin. He tried to use his powers to survive the blast that was within his body, but ended up spontaneously combusting while reaching out to Alex.
When Erik and Charles later returned, the mutants informed them of Darwin's demise, with Raven adding up that "(they) can't even bury him". Erik then states that their fallen teammate should be avenged.
Reactive Evolution - Darwin was able to adapt his body to any environment. He demonstrated various aspects of this ability, including growing gills when submerged in water, turning into iron when under extremely high degrees of heat, or growing thick body armor when attacked.
Professor X - Former Mentor, Former Teammate, and Friend
Magneto - Former Mentor, Former Teammate, and Friend