Rusty

Rusty was an arms dealer who was employed by Oswald Chesterfield Cobblepot, aka the Penguin, who was active during New Year's Eve of Batman's second year of crime fighting.

History
Acting as one of Penguin's arms dealers, Rusty sold various criminals some cryo-guns that had been supplied by Mr. Freeze in exchange for their aid at raiding GothCorp and abducting its CEO, Ferris Boyle, to ensure a crime wave that involved freezing people developed in Gotham City. After Batman failed to apprehend Freeze or prevent his abduction of Boyle, the Caped Crusader tracked down Rusty in order to locate Freeze, based on what one of the criminals stated after he was interrogated by him in the Ballroom at Wayne Manor. Meanwhile, a cop proceeded to stumble upon Rusty and tried to apprehend him in the Diamond District alongside his goons. However, Rusty ended up freezing the cop easily due to his being ill-equipped to deal with the cryo-gun's cryogenics-based ammunition. Rusty then left to make a sale, and also had his men keep guard, though he was unaware that his cryo-gun was leaking. Batman later uncovered both the frozen cop and the leak trail, and tracked Rusty down to another area in Coventry just as he was about to make a sale to some crooks, who were more curious as to how it froze people than how to shoot it. After he subdued them, Batman then interrogated Rusty, and demanded to know where Freeze was. Rusty then revealed that Freeze was headed to GothCorp, and he also revealed GothCorp's access codes as proof when Batman did not believe his claim due to GothCorp not developing weaponry, let alone cryogenic-based weaponry. Rusty's words proved true and was the first set of evidence of what really happened that caused Mr. Freeze's origins.

Powers and Abilities
Rusty was an arms-dealer, and was also shown to be a good shot, as evidenced by his quickly freezing a cop despite being caught by surprise.

Trivia

 * Rusty's name wasn't given in either Batman's crime scene analysis of the frozen cop or his encounter with the arm's dealer, although he was identified as such by the criminals in the area where the frozen cop was found, where they referenced the cop being frozen by him.