In a Pre Crisis Golden Age story, Batman participates in an isolation chamber experiment which involved him being trapped inside a chamber for a long periods of time. The experiment was conducted by the insane Dr. Simon Hurt. During that time Gordon was replaced by Commissioner Vane. After Batman left the project, Vane began to fear that Batman may not be around for a long time and began thinking of a way to replace him. He collaborates with Dr. Hurt to create 'replacement' Batmen if the original Batman should perish.

According to Dr. Hurt that Batman's most likely motivation for fighting crime was a great tragedy in his life. They then choose police recruits and psychologically scars them in order to make them into a Batman.

The Black Casebook

Years ago, Batman had a vision where he encountered three Batmen who were 'figures' of what Batman believes will happen if he ever cheated on his war on crime. The first Batman was a marksmanship who (obviously) uses gun, the second was the Bane Batman who uses Bane's venom and Hugo Strange's Monster serum and the third Batman was the man who sold his soul to the Satan.

Space Medicine

The Third Batman invades Gotham P.D. He begins spraying the headquarters with sleep gas. Gordon bursts in to stop him but the Third Batman shows him a Police badge. James Gordontries to negotiate with but he captures Gordon and takes him to the roof where he lights up the Bat Signal. Meanwhile Bruce is skydiving with Jezebel Jet when he sees the Bat signal. Bruce tells Alfred that he is going to see what is going on and to tell Jezebel that his parachute veered off course. Batman arrives at the rooftop and fights with the Third Batman. The Third Batman shoots the real Batman in the chest and he begins to suffer a heart attack. Batman lies on the roof top and experiences a flash back from deeply buried memories (you know stuff he doesn't want to remember). He relives the night when he was partly responsible for the death of Joe Chill. Sleeper then revives Batman and puts him in a chair and binds him with shackles. Batman then faces Sleeper carrying a drill in a vaguely familiar chamber.

The Isolation Chamber

Sleeper tortures Batman and Batman slowly begins to piece things together. The room he is in is way below in Gotham P.D and is the chamber where Batman once participated in the Isolation Experiment (follow this link: The Three Ghosts of Batman for more info). Batman deduces Sleeper's identity to be Lane. A man whose Family is said to have been killed by Satanists and he is a former police recruit trained and emotionally scarred in order to become a replacement Batman. Lane himself has participated in the isolation experiment. Batman himself begins to relive the nightmare of that experiment but manages to escape from his shackles by dislocating his shoulder. Batman proceeds to punch out Lane but meets with the Bane-Batman instead. Gordon meanwhile forces one of the cops Officer Farelli to talk and reveal to him about what is going on. As Bane Batman was about to crush Batman's head, Gordon and the Farelli comes in and shoots Bane Batman in the head. Lane however escapes. Batman gets up and begins thinking about his life and the direction it's taking. He fears that his training and years of training might not be enough to save him from the ultimate evil, if such a thing is really out there in the shadows. Batman meets Lane who is watching on the other side of a fence. Batman proclaims that Batman is finished!

666:Hour of the Devil

In the post apocalyptic future, Batman is dead and Damien Wayne has sold his soul to the devil in order to keep Gotham safe. Damien, as Batman, takes down a dolloid created by Professor Pyg and saves a little girl. Commissioner Barbara Gordon arrives and accuses Batman of killing Candy Man. Batman quotes the poet of Yeats. He then flashes a powerful light: "Welcome to Bethlehem where the forces of light meets the forces of darkness!" He then escapes in the Batmobile to his penthouse. He tells his cat, called Alfred, about other murdered super villains and looks at the news, the world is in chaos with dirty bombs being thrown, war, famine, heat waves.  The the world is falling apart and Armageddon is coming. Batman points out the location of the death of 5 crime bosses Barbara mentioned earlier and learns that it forms a pentagram. In the middle lies Hotel Bethlehem. The Anti Christ Batman (Sleeper) arrives there to ensue chaos over Gotham on the eve of Armageddon. Damien/Batman arrives and slaughters Sleeper's henchmen . Damien then faces off Sleeper and blasts him in to a pool. Sleeper rises out of the water and walks on it's surface.

Damien then claims that the devil did not tell the Anti-Christ Batman that Damien himself has sold his soul to the devil when he was fourteen to keep Gotham safe. Damien/Batman proceeds to viscously kill Sleeper. He rips Sleeper's flesh across the mid section. Damien then kills Sleeper by twisting his neck as an explosion occurs nearby. Barbara Gordon arrives and orders the GCPD to shoot and kill Damien Batman. Damien is shot several times in the chest but gets up unharmed. Barbara asks "What are you?" and Damien responds that he is the best friend she's got. Batman then claims that Apocalypse is over until he says so.