Not much is known about Roderick Krupp, except that he had long made his home in the Tower of Shadows, amusing himself with macabre tales he had uncovered. He earned the name Digger from his practice of telling victims his stories as he buried them to death.
At some point, the vigilante called the Shroud contacted Krupp to join his team of criminals called the Night Shift, who would use the Tower of Shadows as their base of operations. Krupp joined with the team on all its subsequent activities until he was captured by the Avenger Mockingbird while attempting to bury two victims in the middle of a street. Presumably, he remains in custody.