Later, Illyana became an early victim of the Legacy Virus and died from it. The loss of his immediate family, as well as brain damage that forced him to remain in armored form, caused Colossus to rethink his position with the X-Men and join Magneto and his Acolytes, who had offered him an alternative to the X-Men's pacifist philosophy of peaceful mutant/human coexistence. Colossus recovered from the brain damage soon after, but decided to remain with the Acolytes of his own volition, hoping he could temper their extremist methods with what he had learned from Professor Xavier.