Victor was a loyal henchman of Gustavo Fring and prominent enforcer in Gus' Drug Empire alongside Mike Ehrmantraut. Spotted by witnesses at the scene of Gale Boetticher's murder, he is currently a suspect for that crime and the DEA has offered a reward for information leading to his whereabouts. The DEA is unaware, however, that shortly after Gale's murder, Victor himself was killed at the hands of Gustavo Fring.
Before Gale's murder, he was tasked by Gus to watch over Walter White and Gale's replacement, Jesse Pinkman, as they cooked meth in order to make sure they met their requirements. Unbeknownst to the two, Victor secretly observed how they made the drug and eventually learned the process in order to take over their positions as Gus's meth cook should they fail. Because of this, he serves as the hidden main antagonist of the second half of Season 3.
Victor first appears as an apparent fellow customer in the Los Pollos Hermanos restaurant, where Walter White has come looking for Gustavo Fring. He suddenly confronts Walter and tersely conveys Gus's non-negotiable offer to purchase Walter's meth and arrange for delivery within the hour. Victor tells Walt that if he doesn't show up within the hour, to "never show his face" at Los Pollos again.
When Jesse Pinkman decides to start cooking again and is looking for a buyer of his new product, Gus sends Victor to deliver the money. When Jesse complains that it's only half of the amount agreed upon, Victor tells him, "That's your half." Later that day, Walt is sitting in his car at a red light. Victor pulls up next to him and tosses a bag of cash in his window, telling the confused Walt, "Your half," before driving away. It is revealed that Gus instructed Victor to give half of the money for Jesse's meth to Walter as a way to convince Walter to cook again.
When Walt decides that Gale Boetticher isn't going to work out as his assistant at the superlab, it's Victor who escorts in Gale's replacement, Jesse. As Gale and Victor make their exit, Walt, guilt stricken, assures Victor that this decision is for the best. Victor coldly reminds him, "200 pounds a week. Got it?".
After discovering Jesse is planning to murder two of his "trusted employees," Gus sends Victor and Mike to retrieve him and bring him to his chicken farm. There, a meeting is held between Jesse, the rival dealers, Walt, and Gus with Victor and Mike merely observing.
After Walt kills two of Gus's dealers, Walt tells Gus that Jesse is "at least two time zones away." Victor guards the lab at all times when Walter and Gale are present and monitors their conversations. Walt suspects Gus is preparing to kill him, and conspires with Jesse in secret to kill Gale, making Walt indispensable as the only remaining cook.
Victor later catches Walt sneaking out of his house to murder his replacement, Gale, telling him there's "a chemical leak in the lab". Walt reluctantly goes along and is greeted by Mike when he arrives; he deduces they plan to kill him. Walt begs Mike to spare him, offering to turn Jesse over. Under the pretext of contacting Jesse to lure him to a meeting, Walt convinces Mike and Victor to allow him to call Jesse using his cell phone. However, instead of arranging a meeting, Walt instructs Jesse to kill Gale before Mike kills Walt, leaving Walter as the only chemist available to Gus. Victor races to stop Jesse from killing Gale, but arrives too late.
Season 4Shortly after Gale's murder, Victor enters Gale's Apartment and is seen by neighbors, who are later revealed to have accurately described him to the authorities. Outside the apartment, Victor notices Jesse sitting in his car, apparently in shock. At gunpoint, Victor orders Jesse to go to the lab. There they join Walt and Mike.
It is revealed that while watching Walt cook, Victor closely studied the procedure and learned the process of cooking meth. He singlehandedly gets a batch ready in front of a stewing Walt and a somber Jesse, and awaits Gus' arrival in the lab. When his boss finally arrives, however, Gus coolly slices Victor's throat using a box cutter. Walter and Jesse then dissolve his body in hydrofluoric acid, echoing Walt and Jesse's previous experience with Emilio Koyama earlier in the series.  The sketch of Victor at the police departmentLater, a composite sketch that closely resembles Victor is seen a couple of times, including by Gus when he is waiting to be questioned at the police station.
Although he is dead, Walt mentions to Jesse that the reason Gus might have killed Victor is because of Victor taking liberties that weren't his, (cooking meth while Walt and Jesse were held hostage by Mike) and "flew too close to the sun" as Walt put it. The police sketch of Victor can also be seen on the DEA evidence board under the name "Unsub Bystander".