He is Norman Smith, once the superhero known as Captain Crusader who retired after nearly a quarter of a century fighting crime. Retirement did not suit him however as he grew old and fat while his superpowers deteriorated. Ten years into his retirement and the birth of his fourth child, a full scaled invasion by the alien Skorrans was launched and almost all of Earth's superheroes as well as its villains were killed along with nearly a billion humans. Thus large parts of the planet fell before the alien invaders.
Save for Captain Crusader who was at first reluctant to join in the fray but finally flew into the skies when the atrocities caused by the aliens grew too much to ignore and in the meantime occasionally fighting against bouts of survivor's guilt.
At one time the sight of an overweight man in outdated long johns was a cause for great amusement among the superhuman community.
Now with the virtual annihilation of said community, no one including the Skorrans and the human traitors who serve them was laughing at Captain Crusader anymore.