Mr. Midnight was an actor named John Caliban. John was having an affair that was discovered by a man named Ellison Wright, who blackmailed John. This took a toll on John. He felt he no choice but to kill his lover and later he suffered from an accident that turned his skin blue due to cosmetic poisoning from his actor's makeup. All of this put John into a madness as he blamed Ellison ruining his life. In a fit of revenge John adopted a new identity as Mr. Midnight and planned to kill Ellison for his crime
Mr. Midnight had an artistic actors soul and his revenge would be poetic. He arranged to have Ellison commit to his blackmailing by sighing a confession an the stroke of midnight at police headquarters in the office of Commissioner Dolan who was there with the superhero Spirit to see it happen. What the the Spirit and Commissioner Dolan didn't know was he had the poison in his fingernails and had scratched Ellison killing him.
No one could figure out the crime but the Spirit did discover Mr. Midnight secret identity and got Mr. Midnight to commit to his crime. This was in part due to Mr. Midnight growing maddness. Mr. Midnight was dedicated to getting away with his crime to the point of killing himself and attempted to do so by jumping into a burning inferno he himself used in the first place to escape. The Spirit saved Mr. Midnight's life and took him back to police headquarters only to have Mr. Midnight take his own live with his poisoned fingernails.