Bertrand Eldon, also known as the Executioner, was the former executioner at Blackgate Penitentiary until he realized he was actually killing innocent people for corrupt officials. After this realization, he became a murderous vigilante called the Executioner.
For 20 years, Bertrand Eldon worked at Blackgate Penitentiary as an executioner and executing criminals that were guilty and put on death row. Years later, he realized that all the criminals he executed were innocent and were set up by a Cabal of corrupt officials comprised of ADA Angus Stanton, Detective Stu Donnelly, and Judge Raymond Calverick.
Being a vigilante and Death
In 2019, feeling extremely horrible with himself and remorseful for the innocents of people he murdered, he decided to revenge on the corrupt law enforcement officials who wrongfully accused others and had murdered by becoming the "Executioner". he then proceeded to attack them using the three methods of capital punishment used in Gotham; the electric chair, a firing squad, and the gas chamber. He started by electrocuting ADA Angus Stanton. Later, he set up a trap that resembled a firing squad to kill Stu Donnelly, in which he succeeded but also accidentally shot Sophie Moore in the process. Hunting for resources for the third execution method, he ran into Batwoman while searching for hydrogen cyanide, but his car knocked her out allowing him to get away with the gas. A short time later, he tried to kill judge Calverick in the latter's courtroom but got interrupted by Batwoman once again. He attacked her but was shot dead by Commander Jacob Kane. His death triggered a dead man switch, filling the room with hydrogen cyanide, which was his plan for Calverick all along. However, Batwoman was able to burn away the gas in the room, saving Jacob Kane's life.