Guido's became Strong Guy in X-Factor (1st series) #72. His last name was revealed in #82.
Strong Guy lost his soul when Layla Miller reanimated him following his death in X-Factor #218. This led to him ultimately becoming the ruler of Hell in #256, a fate reversed in Thunderbolts (2nd series) #22. Illyana Rasputin reportedly helped Guido regain his soul prior to New Mutants: Dead Souls #1.