Walter White has a fearsome reputation in Breaking Bad, he is "the one who knocks" after all, but how many times did Bryan Cranston's character actually get his hands dirty? At the core of Breaking Bad is Walt's transformation from a downtrodden chemistry teacher who passed up a chance for greatness into one of the foremost drug manufacturers in the world, but that transition doesn't come without a price. Walt detests the idea of violence when first breaking into the meth business and always hopes to find a less deadly solution. By the end of the series, however, Walt has come to the conclusion that the deaths of others are an unfortunate consequence of the path he has chosen.
Gradually, Walt's mercilessness starts to instill fear in even the most hardened of New Mexico's criminals, and it's natural to assume that the great Heisenberg has killed as frequently as other big names like Gustavo Fring and Tuco Salamanca. This belief is somewhat misleading, since Walt is a master of delegation, and many of his most infamous killings were actually carried out by others, albeit at Walt's behest. The Great Heisenberg convinces Jesse to assassinate Gale, takes advantage of a long-held grudge to have Hector Salamanca blow Gus' face off, pays Jack's men to commit the prison attacks and allows Jane to die of a drug overdose. While more murders are carried out for Walt than by him, the former high school teacher's hands are by no means clean.
Throughout Breaking Bad's entire run, Walt personally executes or assassinates the following, in chronological order:
- Emilio - With his life under threat, Walt traps Jesse's former associate in the RV after setting off a deadly chemical reaction. This act is done entirely in self-defense, but Walt and Jesse are forced to dissolve Emilio's body in a bath of acid to cover up their crimes.
- Krazy-8 - Another small-time drug dealer, Mr. 8 is caught up in the RV along with Emilio but somehow survives. Walt and Jesse manage to restrain him, and this presents Walt with his first true moral dilemma. Since Walt knows Krazy-8 will attack him if he's set free, self-defense could also be argued here, but it's far more morally gray than with Emilio.
- Gus' two dealers - Once Walt's meth business begins to take off, he naturally encounters competition for turf. Walt tries to avoid a showdown, but Jesse has other ideas and confronts their rivals directly. Seeking to protect his friend, Walt kills one dealer by running them over and then shoots the other. There's a noticeable reduction in his emotional response on this occasion.
- 2 meth lab guards - After arranging for Hector Salamanca to kill Gus, Walt breaks into his rival's secret meth lab to liberate Jesse, killing two guards in the process. He displays very little remorse at this stage.
- Mike Ehrmantraut - The first time Walt personally kills a major Breaking Bad character comes surprisingly late in the day, namely with the murder of Mike in the show's final season. Mike has to die as part of Walt's attempt to tie up loose ends and ensure nothing is traced back to him. Walt does show a modicum of remorse here, presumably because he's killed someone he previously seemed to like.
- Lydia (probably) - Walt's former business associate double-crossed him by siding with the Nazis but Walt would be sure to have his revenge, replacing her drink sweetener with ricin. Although Lydia's fate is left ambiguous in Breaking Bad, she's confirmed to be close to death in the El Camino movie. Still, a miracle recovery might've happened...
- Jack & his Nazi gang - After a period of exile, Walt resolves to finish off those who wronged him and free Jesse Pinkman. As part of his last stand, Walt takes down Uncle Jack and 6 other members of his gang using a trunk-mounted machine gun, sacrificing himself in the process.
While Walt perhaps doesn't directly kill as many people as his enemies (and, indeed, the audience) might assume, he's certainly sunk to those depths when necessary and, as far as Walt's family are concerned, a single death is one too many. Walt may not kill as frequently as most protagonists of cartel-based gang dramas do, but this helps ensure that each occasion packs a significant impact and feels like a significant step in Walt's descent as a character in Breaking Bad.