Langstrom was locked in an isolation chamber and broke down in tears upon discovering Francine's fate. By the time the Batmobile arrived at the GCPD Lockup, Man-Bat had returned to normal. Finding it ineffective, Batman hunted Man-Bat down a second time, this time knocking him unconscious and injecting him again on Founders' Island.

Batman later injected Langstrom with the cure on Bleake Island. While Batman investigated his history, Man-Bat continued to circle Miagani Island.

A brief battle ensued, during which Batman was able to take a blood sample. Man-Bat traveled aimlessly around Gotham before he encountered Batman on Miagani Island. Out of control of his actions, the creature destroyed the lab, inadvertently and apparently killing Francine in the process, before escaping out into Gotham. However, the effects were far stronger than Kirk anticipated, causing him to mutate into a human-bat hybrid. Finally developing a method of splicing the DNA of desmodus rotundus (the common vampire bat) into human DNA, Kirk tested it on himself in hopes to cure his hearing loss. Kirk eventually developed chronic deafness, providing him with a challenge and an opportunity to test his theory. The two had a happy and functional marriage despite financial issues caused by the widespread skepticism towards their research. The two aimed to cure human diseases by using genetic splicing. Kirk met his future wife, Francine, in graduate school.

Creature of the night arkham knight