The Dealer was created by writer Scott Snyder and artist Jock (Mark Simpson). His first appearance was in in an issue of Snyder's Batman epic The Black Mirror. The issue that he first appears in is Detective Comics #872 - The Black Mirror, Part Two of Three; Skeleton Cases, Part 2 of 3.
Major Story Arcs
The Black Mirror
Shortly after Bruce Wayne appointed Dick Grayson to be the Batman of Gotham City, a string of mysterious crimes occur with a series of weapons and abilities that are utilized by Batman's rogue gallery. First, Edward Lamont IV, a young rich boy who was kidnapped by Killer Croc ingests the same serum that enhanced Killer Croc's advanced skin condition. Edward mutated himself so he could get revenge on those who bully him. It seems Edward’s uncle is a dirty cop and he was the one who gave his nephew the Croc serum. Dick Grayson subdues Edward after he devoured his tormentors. James Gordon and Dick use the laboratory at Wayne Enterprises to remove the serum from the Edward’s body.
Afterwards, Dick went to Edward's house in Palisades to talk to his mother. By this time, the dirty cop is already aware of Edward’s apprehension so he takes the initiative by wiping out all loose ends. He places a Mad Hatter microchip on his sister and tells her to kill her butler and then murder the Batman when he arrives. The uncle then situates himself outside of the house to make sure everything goes according to plan. Batman arrives and finds the butler bleeding on the tile floor.
The butler proclaims Edward’s innocence but before he could tell Batman about who gave Edward the Croc serum, Edward’s mother comes out from the shadows and shoots the butler with a shotgun. The mother runs out of shells for the shotgun and the uncle realizes that his plan is going awry. The uncle then tells his sister to run upstairs and jump out of the nearest window. Unfortunately, Batman is unable to save the woman but he does manage to pick up the Mad Hatter device from off the floor then he notices a police car speeding away from the house. Dick memorizes the number on the police car and tells Gordon to be ready at the precinct when the uncle returns.
Gordon arrests the uncle and brings Batman to the interrogation room. It turns out the uncle is the officer who is in charge of the evidence locker at Gordon’s precinct and he has been selling various items from Batman’s rogues to someone named the Dealer. Dick and Gordon leave the room to compare notes while the uncle waits to be processed. Unfortunately, someone placed airborne spores in the ventilation system that leads to the interrogation room. When Gordon and Dick return to the room, they find the uncle covered in vines with plants growing out of his body.
After some help from Oracle, Dick learns that the Dealer runs an underground organization called the Mirror House, where secret auctions are held and items from different criminals are being auctioned off to the rich or famous but only the highest bidder gets the prize. Oracle and Dick also learn that the Dealer often goes by the alias of Etienne Guibourg, an abbot who was part of the Affair of Poisons during King Louis XIV’s reign. Red Robin manages to get a lead on a possible Mirror House invitee for Dick. Dick tails the invitee, detains him and takes the invitee’s invitation to the Mirror House. Dick arrives at a rundown building where he notices several members of Gotham’s elite in front of the building and each of them is wearing a gas mask.
Dick was given a mask then led down an old, abandoned banquet hall along with the other invitees. They are later greeted by the Dealer who explains to all of his guests that the room is being pumped with a deadly gas just in case someone isn’t who they say they are. The Dealer begins to the auction with blood stained crowbar. The same crowbar used by the Joker to mercilessly beat Jason Todd nearly to death. However, the Dealer’s henchmen recognized Dick Grayson because Dick’s face was present during Bruce’s announcement of Batman Inc. The henchmen gave Dick a faulty mask and Dick began to breathe the gas. Fortunately, the gas only knocked Dick out rather than kill him. Dick nearly passes out as the Dealer tells his demented guests to tear Dick apart.
Even though he was dazed by the fumes, Dick powered on through and took out his attackers at the Mirror House. Dick then makes his way to the outside and grapples to a nearby building so he can recuperate. The guests at the Mirror House leave since the auction has called off and the Dealer’s organization has now become compromised. Dick follows the Dealer to the Gotham airfield and sneaks onto the Dealer’s getaway plane. Dick subdues the Dealer’s henchmen in the cargo bay then he activates the cargo bay door.
As Dick began to dump the Dealer’s merchandise out into the open air, the Dealer injects himself with a combination cocktail of Man-Bat serum and Venom. The Dealer mutates and attacks Dick. Dick puts an end to the Dealer’s rampage by using an explosive batarang to destroy one of the plane’s wings. The Dealer falls out of the plane and Dick glides to safety. The plane crashes in Gotham Bay and all of the Dealer’s merchandise is lost at sea. As for the Dealer, his body was never recovered so it’s possible the Dealer utilized his new wings and flew off.
The New 52
After Death of the Family, Amusement Mile was ruined and a group of scavengers looked through the ruins for artifacts The took the artifacts that they found to the Dealer to sell them to him, presenting him with a Flying Grayson's uniform that had been graffitied by the Joker.