Better Call Saul Season 4 is set to explain one plot thread that's been dangling since Saul Goodman's very first appearance in Breaking Bad Season 2 all the way back in 2009. When he was introduced, Saul was a comedic foil to the darker descent of Walter White, helping him launder money and escape capture with a constant, removed sarcasm.

Getting his own spinoff, however, has vastly changed how the audience views Saul. Real name Jimmy McGill, he is a tragic figure, a morally-flawed yet well-meaning person pushed towards bad things by the doubts of those around him, rather than the inherent greed that turned Walter White into Heisenberg. We know where he's heading - both in terms of the man in the hat and his lonely life working in a Nebraskan Cinnabon - and that he's going to fall into a life he doesn't deserve. What's been so impressive about this heavy dose of dramatic irony is how carefully Vince Gilligan and co. have avoided the common prequel pitfall of relying too much on the original.

Related: Better Call Saul Has Become Breaking Bad (And That's Okay)

That's not to say we've not had some delectable Breaking Bad connections. Already in Better Call Saul we've seen a lot of how Jimmy transforms: we've seen him meet Mike, learned where the Saul Goodman pseudonym came from (and had a taste of the legal reasons he'll use it), and in parallel witnessed the war between Gus Fring and Hector Salamanca (and that's not mentioning the wealth of Breaking Bad cameos there's been along the way). However, there's one key aspect that hasn't been addressed yet: Lalo.

Saul Mentioned Nacho And Lalo In His First Breaking Bad Appearance

Saul Goodman Kidnapped in Breaking Bad

Saul enters Walter White's saga with extreme reluctance. When Badger is caught dealing, Jesse convinces Walt to go to a "criminal" lawyer to get him free. That lawyer is Saul Goodman, now fully lost in the world of saving law-breakers, and he's if anything too efficient; his plan involves having Badger give the emerging Heisenberg up to the cops. When he turns down a bribe to curb that, Walt and Jesse kidnap Saul, taking him to the desert in a bid to scare him into compliance. This eventually leads to a long and intermittently fruitful-slash-destructive relationship, although it's what Saul says in that fake kidnapping we're interested in.

At first, Saul thinks he's been kidnapped by someone else. He begs, "Oh no no no no. It wasn’t me. It was Ignacio. He’s the one!", and then realizing his current predicament isn't what he thinks, asks "Lalo didn’t send you? No Lalo?"

First things first, Ignacio is none other than Nacho, a key player in Better Call Saul. Introduced first as one of Tuco's henchmen, Nacho becomes involved with both Saul and Mike, hiring the latter to get rid of his boss, which in turn gets him further tied in with Hector Salamanca. In Season 3, he became increasingly disillusioned with his part in the drug trade, plotting to kill Hector as a means to escape. The last we saw him, he managed to instigate a heart attack in Hector, only to pique the suspicions of rival Gus Fring. Saul's namedrop in Breaking Bad, set some five years later, suggests that he survives whatever is to come and winds up on some shaky terms with the lawyer.

Related: Better Call Saul Creator Teases Even More Post-Breaking Bad Story

However, we're yet to have an indication of who Lalo is or how he fits into the bigger picture. That won't stay this way for long, though.

Page 2 of 2: Lalo In Better Call Saul Season 4

Bob Odenkirk Better Call Saul Season 4

Lalo Is Coming To Better Call Saul Season 4

Given that he was mentioned in the very first appearance of Better Call Saul's main character, there's long been anticipation of Lalo appearing in the show; unlike Gus or Hector, who Saul only has tangential relations to pre-Breaking Bad, here's someone with a genuinely destructive influence on his past. That he hasn't appeared is very typical of Vince Gilligan's measured approach to prequel storytelling.

But Lalo's arrival is on the horizon. Bob Odenkirk told Deadline that Lalo is the must-happen event in Better Call Saul, while Wired reported the name was included in a set of characters in the writers' room. Most recently, at the AMC Summit Peter Gould teased that a major, albeit unseen, Breaking Bad character would appear in Better Call Saul Season 4, confirmed by Melissa Bernstein to be Lalo. He's coming soon, so the question now becomes who Lalo is, and how he fits into both Better Call Saul's narrative and the bigger Breaking Bad pantheon.

How Will Better Call Saul Season 4 Introduce Lalo?

Mark Margolis as Hector Salamaca and Michael Mando as Nacho in Better Call Saul

Long-standing theories have existed that Lalo is actually a pre-existing character: Gus, Hector, Tuco, Skinny Pete. However, not only does the recent promise of the character entering the fray work against that, as does the far too neat manner by which it would tie Saul's story together; it would mean Walt coincidently happens upon a lawyer with a direct link to one of his future foes, something Better Call Saul has so far handled elegantly (see how Jimmy and Gus are unable to meet).

Related: Better Call Saul's Breaking Bad Connections

One of the most coherent theories from the endpoint of Season 3 is that Lalo is a cartel enforcer sent by Don Eladio to clear up the mess of the Fring-Salamanca conflict that is now dangerously imbalanced; the Better Call Saul Season 4 synopsis says Hector's heart attack "throws the Cartel into chaos" and "Nacho finds himself in the crosshairs of deadly forces". It's suggested that Lalo is that force, suspecting Nacho of plotting to kill his boss. Jimmy/Saul then helps him go into hiding via Ed, the disappearer from Breaking Bad. This satisfies a lot of what we need from Lalo: he's a suitably big fish to be scary; Nacho is intrinsically linked; and the thing that Saul claims he didn't do would be, presumably, injure Hector. It would also be a bittersweet end for Nacho, whose arc has been on an opposite trajectory to Jimmy; he gets out of being a criminal but has to live apart from his aging father. If Better Call Saul does end with Jimmy estranged from Kim Wexler, then it's particularly fitting.

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While Lalo is mentioned by Saul very early on, that doesn't have to mean that he's going to be a dominating presence in the final act of Better Call Saul. After all, Saul isn't exactly in hiding after whatever happened with Nacho; his face is plastered all over billboards. All Lalo really needs to be is the biggest looming threat over Jimmy as he ascends through the criminal legal system; the go-to "oh sh*t" moment if anything does go wrong (and given the company Saul will soon keep, that says a lot), rather than the inciting incident. The main thrust of Better Call Saul is Jimmy's descent, and that's something much more internal and relationship-based.

And that, perhaps, is the real brilliance of the show. It's that rare prequel where connectivity to the original isn't the dominating story drive. Everything in Better Call Saul will line up impressively with Breaking Bad (although Vince Gilligan does regret one of Saul's early throwaway lines), but even Lalo is just one part of a bigger picture.

Next: Better Call Saul Season 4: Every Update You Need To Know