Darwin is a mutant whose body is under a constant state of reactive evolution, which allows him to adapt to survive in any situation. He was brought in alongside Vulcan to join the X-men, but were seemingly killed when trying to save the original X-men from Krakoa, the living island. In actuality, Darwin absorbed the essences of his fallen teammates and evolved into an energy state, which allowed him to combine with Vulcan and help them both survive as the island was shot into space with them trapped inside.