He roamed the underworld by night, in search of villains to bring in, like a good superhero should. But in the daytime, he hung around the jail where he was a convicted inmate.
Of course, the fact that he was a resident of a jail cell with the lucky number 711 at Westmoor Prison, from which he obviously derived his superhero name, was just a ghastly mistake. In fact, when he was known as Daniel Dyce, he was a district attorney. But he had a pal named Jacob Horn, who looked exactly like him, and Jacob was in the process of going down for a crime he actually did commit. Just before he went to trial, Jacob begged Daniel to let him out for just a little while, so he could be at the hospital when his son was born; and what the heck, Daniel was a big enough idiot to let him do it. Since they could pass for each other, and since Daniel had an "in" with the system, they simply traded places for the evening.
But Jacob never made it to the hospital. He got hit by a car on the way, so nobody came to relieve Daniel. The dead guy was identified as the district attorney, and the one that was left wound up in the slammer. Fortunately, the prisoner was able to dig a tunnel from his cell, through which he could come and go at will. He had a fine time all night as the scourge of the criminal class, but was always back in time for morning roll call. He even handed out fancy cards, supposedly showing the crooks what fate awaited them, but in reality, they represented the fate that had already befallen the masked hero.
711's crime fighting career ends when he is killed by a criminal, however as a ghost he is able to induce the only witness to the crime to bring the murder to justice and start a crime fighting career of his own as the teleporting mystery man, Destiny.