AMC's Better Call Saul does such a great job of creating villains that are equally theatrical and terrifying, and it's a big part of why the show has become so successful. It's hard to say who is and who isn't a villain in the Breaking Bad series, as even the characters who aren't murderous drug lords are immoral lawyers out to get Jimmy.
Even Jimmy himself is somewhat of a villain. But broadly speaking, the antagonists in Better Call Saul are ones who intentionally negatively affect Jimmy or Mike's lives, whether they're trying to discredit Saul as a lawyer or outright murder either of them.
Don Eladio
So many Breaking Bad characters have shown up in the thrilling spin-off, and Don Eladio's appearances are underrated ones. Just like the deadliest and most sadistic characters, Eladio is charming and charismatic, and that's what makes him one of the most exciting characters to watch.
Just like in Breaking Bad, Don Eladio doesn't have much of a physical presence, but his influence on the events in the show can be felt. Eladio is constantly pulling the strings behind the scenes, and he's at the top of the food chain, as it's him who everyone has to answer to. Living in Mexico, Eladio knows exactly what he's doing, as he keeps everything, including the cooks, the henchmen, and even some high-ranking members at arm's length.
The Twins
Leonel and Marco Salamanca are two of the most iconic villains in Breaking Bad. Their suits, skull-capped boots, and bald, shiny heads are instantly recognizable. And along with the fact that they don't talk, not even with each other, makes the twins two of the most intimidating antagonists in the Breaking Bad world.
It's hard to call the hitmen villains of Saul, and it could even be the opposite, as the only real interaction with Jimmy was when they gave him a bag full of $7 million to deliver, which came with an extra $100,000 for the smiley lawyer. However, they're still villains, and they unforgivably threatened Mike's granddaughter's life. And given how the series is seemingly heading towards a war with the Salamanca family, it's likely that it isn't the last audiences have seen of the twins, and they and Saul will probably cross paths again.
Tuco Ramirez
The very first episode of the show proved how much of a contender Better Call Saul is on the TV landscape and that it isn't just any TV spin-off. Part of how Vince Gilligan and the crew did that was by bringing back a fan-favorite villain and one of the most entertaining Breaking Bad characters, Tuco.
In the prequel, Tuco is as terrifying and unpredictable as ever, and he has the most unnecessarily and comically big pistol any viewer has ever seen. But he's still in his drug dealing infancy in the show, and he isn't much of a threat sitting in jail. That's not to mention that he got his sentence prolonged after stabbing an inmate. He was thrown in jail in season 1, and won't be released until the Breaking Bad era.
Howard Hamlin
There are so many movie jerks audiences hate, but when it comes to TV, there's no bigger jerk than Howard Hamlin. Despite how well-meaning a character is, audiences will always hate them if they try stopping the protagonist from following through on their ambitions, because that's what viewers want to see, even if the ambitions are criminal. That's why Skylar was so hated in Breaking Bad, and that's why Howard is so hated, as he vindictively keeps Jimmy from being a successful lawyer at every turn.
But it was revealed that Howard didn't actually have as big of a hand in keeping Jimmy from being a lawyer as much as he thought, and it was Chuck that was holding Jimmy back. In fact, after Howard wanted to let bygones be bygones with Jimmy after Chuck's death and even tried legitimately hiring him, it was Jimmy who became something of a villain. The smart-mouth lawyer threw bowling balls at Howard's car and got up to all sorts of typical Saul-like behavior to ensure Howard had the worst life possible.
Hector Salamanca
Ultimately, Don Hector's name foreshadows his fate, as "hector" translates to "to restrain" in Greek, referring to how he's always restrained to a wheelchair. But for as much of a fascinating character as he was in Breaking Bad, his origin and how he came to be wheelchair-ridden were never explored.
Thankfully, Better Call Saul goes into great detail about it, and it even reveals what audiences never knew; that Hector is an evil, murderous, and maniacal member of the cartel. Don Eladio's right-hand man kills innocent civilians without giving it a second thought, anything the twins do is ordered by him, and worst of all, he threatened Nacho's father.
Gustavo Fring
Gustavo Fring was undoubtedly the best villain of Breaking Bad, and the phrase "if looks could kill" has never applied more to anybody in life than to Fring, whose piercing stare intimidates even the viewers at home. While Jack Welker might have been genuinely terrifying and the most despicable human being in season 5 of Breaking Bad, there's nothing more entertaining and engaging than the chess game between Walter White and Fring for the entirety of seasons 3 and 4 of the show.
Fring in Better Call Saul is just as much of a thrill to watch, arguably more so, as it sees him building his empire. Fring is professional, as he'll warn people once, and even a second time, but if he has to warn them a third time, he might not be as friendly. And though Fring survives to the end of Better Call Saul, it'll be interesting to see how he does.
Chuck McGill
The soon-to-be Saul Goodman had never been more empathetic and caring than when he was around his brother, as he delivered Chuck groceries, newspapers, and he even humored his fake medical issues. But it was a one-way street, as all Jimmy got in return was abuse, and that's why fans hate Chuck McGill.
For Jimmy's whole life, Chuck had been bullying and tormenting him and using his position as a powerful and respected lawyer as a way to make Jimmy feel bad about his own life. Jimmy might have lied to win the lawsuit against Chuck, but it's no different from the way Chuck had treated Jimmy and kept him from becoming a lawyer for so long.
Lalo Salamanca
Lalo Salamanca is smart, physically strong, and he has that same charm that Don Eladio has, making him the most fearful villain of the entire series. The character was able to outsmart and takedown a whole group of assassins all by himself. And though it's safe to assume that Lalo doesn't last past the season 6 finale, as he doesn't appear in Breaking Bad, it's also safe to assume that he's taking everyone down with him.
He's such a terrifying villain that whatever his fate is at the end of season 6, he still haunts Saul in Breaking Bad. When Walt and Jesse first kidnap Saul in season 2 of Breaking Bad, Saul fears they're Salamanca's men and he even starts blaming Nacho for whatever it is that happened.