There is also an Evil Gargantuman, in a dimension where things didn't quite work out for him.
Missing But Still In Action
Being stronger and tougher than your average man meant he was destined for something special in his time in the military. His group, sent deep into the south ameriacal jungle on a covert mission, was ambushed and captured. After weeks, it became clear that no-one was coming to rescue them, perhaps the government had to maintian 'plausable deniability', but no matter. They had to do something to get out of this mess themselves. The escape attempt went disasterously and quickly turned into a massacre, as his comrades were quickly gunned down his mutation fully revealed itself, fighting his way out of the camp, shrugging off gunshots and grenades alike.
After being left for dead by his superiors, he figured he was actually dead to them, or at the very least classified M.I.A, and so set off to Paragon City, to make a life as his own man, to become a Hero.