The unnamed drug dealer is a minor character appearing in Grand Theft Auto V.
Not much is known about him beside that he is a member of the Ballas.
Events of GTA V
Stretch sets Lamar up by telling him to buy weight from the dealer in Grove Street. Without suspicion, Lamar comes to Franklin's house to persuade him to do the deal together which incidentally ends up having Trevor taking part.
The trio comes to the dealer's house, the door opens suspiciously as all three men are presented with a white block wrapped in plastic. Once it's cut open, Lamar gets a taste and is extremely eager to hand over a large sum of cash for it. Trevor however, is much more skeptical. He asks if they can take a sample from the other side of the brick, but the dealer refuses to do so and instead plays hardball. As Trevor grows frustrated, he snatches the block from out of the dealer's hands, and snaps it in half, proving his skepticism to be correct after all; it was just drywall filler.
The dealer reacts by calling the aid of his fellow members and immediately shutting the door. Trevor, Franklin and Lamar have to fight their way out of Grove Street. The dealer survives the shootout since he doesn't take part in it.