Killer Bat

Dr. Isaac "Bruce" Sidney (a.k.a.) the original Killer Bat is a fictional comic book supervillain and an occasional enemy of Gun and on-and-off superhero. He had greatly admired Gun and everything he did, and wanted to accompany him on his adventures to save the city. He, along with his partner, Will Nefarius gathered chemicals, DNA samples and drugs to create a serum. When Bruce tried it out on himself, the results were catastrophic, resulting in the birth of first Killer Bat.

G.U.N. The Animated Series

 * On Steel Wings (debut)
 * Terror in the Sky

G.U.N. of Steel

 * Animal Act

G.U.N. World at War

 * Doomsday Part II
 * The Darkside of Town Part I