The man who would become known as Killer Moth was originally inmate #234026 in Gotham State Prison. Deciding that the criminals of Gotham needed a guardian just as the honest citizens had Batman, he became determined to fill that need.
Upon his release from prison, the inmate used his ill gotten fortune (accumulated before he went to jail) to create the identity of Cameron Van Cleer, a wealthy socialite.
Beneath his mansion, Van Cleer excavated an elaborate cave equipped with a modern crime lab in which he hoped to develop the most scientific methods of making a crime impossible to solve. After completing a complex arsenal, then donning a dark and mysterious costume, Van Cleer offered his protection services to the underworld as the Killer Moth.
For a price, Killer Moth guaranteed to protect Gotham City's criminals from capture. All participating gangsters were issued with a Moth Signal - a flashlight that emitted an infra red distress signal visible only to Killer Moth through special glasses hidden in his helmet.
Eventually, Killer Moth found himself in conflict with the very man he had tried to emulate - Batman. After several encounters with the Caped Crusader, Killer Moth appeared to fall to his death.
Killer Moth first appeared in Batman #63 and was created by Bill Finger and Lew Schwartz.
Pre-Crisis and Silver Age
Several months later, Killer Moth returned, his reputation as a guardian for Gotham's underworld totally ruined by his defeat at Batman's hands. Determined to take revenge, Killer Moth once again confronted the Dark Knight Detective and was again beaten. In the course of this encounter, Batman discovered that KM was actually Van Cleer, and he permanently destroyed the costumed criminal's secret identity.
Months later, Killer Moth escaped from prison. Having decided to assume a new secret identity by kidnapping and impersonating a wealthy and influential Gotham citizen. Killer Moth also invented the alias Laszlo Furlenbach in order to serve as a liaison between him and other criminals thereby eliminating any chance of being implicated should any criminals "drop a dime" on him. Killer Moth captured Bruce Wayne and was astonished to discover that Wayne was Batman's secret identity. Wayne escaped capture and tracked down Killer Moth just in time to see him being gunned down by a former crony who erroneously believed that Killer Moth had doubled crossed him. A bullet lodged in Killer Moth's head, needing surgery that would remove the part of the brain where recent memories are stored. Thus Killer Moth forgot all about Batman's secret.
Years later, having no memory of their prior encounter, Killer Moth again tried to kidnap Bruce Wayne but was thwarted by the intervention of Barbara Gordon, daughter of Police Commissioner Jim Gordon. As a result of this, Barbara became Batgirl. Killer Moth has confronted Batman a number of times since then, but on each occasion has ended up back in jail.
Post-Crisis and Modern Age
Drury Walker is Killer Moth, using the false name Cameron Van Cleer. He forms the Misfits with Catman and Calendar Man. During Underworld Unleashed he sells his soul to Neron, becoming the monster Charaxes. In one story he lays hundreds of eggs that turn into duplicates of Drury. He was later ripped in half by Superman-Prime and presumed, again, to be deceased.
A new Killer Moth appeared fighting Robin in Face the Face. He later appeared in Gotham Underground, where he was put into critical condition because of an ambush set up by Tobias Whale.
This new Killer Moth was found in his hideout by Ray Palmer and Ryan Choi, the former and latter heroes, both known as The Atom. Ray Palmer uses his shrinking power to go into Killer Moth's sinus cavity to gain answers about who murdered a friend of his. Killer Moth gives the answer, Prometheus, and is left in agony by the two Atoms.
Later, several villains clad in the Killer Moth costume are seen battling the Secret Six. At least one is killed by Deadshot.
In the new 52 Killer Moth is seen during the Gotham City blackout attempting to kidnap and ransom Moira Queen, unfortunately for him both Batman and Green Arrow come to her rescue and he's beaten and detained.
Major Story Arcs
Killer Moth as appeared in such arcs as Batman's "Testimony of Luthor", Detective Comic's "Dead Reckoning", and Batgirl's "Year One."
Powers and Abilities
Killer Moth relies is he equipment and does not have super powers. His moth mobile, steel-line (swinging rope), and his cocoon gun are just some of the weapons he uses.
As Charaxes he obtains superhuman strength as well as a protective exoskeleton. He also has wings, which allow him to fly, and can secrete an acidic substance that traps his victims and dissolves their bodies.
Live Action Appearances
Killer Moth first appeared in the live-action 1960's Batman TV show, played by Tim Herbert. He was the first villain Batgirl fought, although the episode never aired.
Killer Moth appeared in two episodes of Teen Titans as a criminal who used mutated moths to commit crimes, and was comically undercut by his demanding daughter, Kitten. He was played by Thomas Haden in his first appearance, "Date With Destiny", and by Marc Worden in his second appearance, "Can I Keep Him?"
He appeared in The Batman episode "Team Penguin" as a wannabe super villain who joined Penguin's team as a lackey. He was transformed into a moth monster by unstable chemicals that he was transporting for the team. He was portrayed by Jeff Bennett.
In the Batman: the Brave and the Bold episode "The Last Patrol", he appeared, sharing many of the characteristics of his original Silver Age character. He was played by Corey Burton
Killer Moth appeared as a boss in Batman NES . He also appears In Lego Batman: the Video Game and Lego Batman 2: DC Super Heroes as an enemy and playable character. His powers are limited flight and he uses a gun. He is referenced in Batman Arkham Asylum in the form of an unlock-able bio. This was his only appearance in the game.
Although he doesn't appear directly, he's featured in one of The Riddler's many riddles. A half cocooned corpse can be seen hanging in a corner of the Aviary. His bio reveals it to be Drury Walker.