Hector Salamanca played a key role in Breaking Bad but details surrounding the character's backstory weren't revealed until Better Call Saul. Hector Salamanca, portrayed by Mark Margolis, made his Breaking Bad debut in season 2 as Tuco's (Raymond Cruz) ailing uncle. Hector went on to play a more prominent role, especially in the demise of Gus Fring (Giancarlo Esposito).
Tuco brought Walter White (Bryan Cranston) and Jesse Pinkman (Aaron Paul) to his hideout in the desert, which is where the pair first met Hector. Having suffered a stroke, the old man could only communicate by ringing a bell equipped to his wheelchair. Walt tried to poison Tuco's burrito but Hector repeatedly hit his bell to warn his nephew, revealing that his mind was still sharp. Hector raised Tuco and his other nephews, Marco and Leonel (also known as the Cousins), to be high ranking members in the cartel. Due to Hector's rivalry with Gus, all of his nephews were murdered. Hector decided he had enough so he orchestrated Gus' murder with Walt by attaching a bomb to his wheelchair. He sacrificed himself in the process but Hector was successful in killing his longtime enemy.
Through Breaking Bad flashbacks, viewers learned that Hector was a member of the Juárez Cartel. He was working for Don Eladio (Steven Bauer) during the time Gus entered the cartel. Don Eladio hosted a meeting between all parties to discuss the future of the cartel, but he wasn't pleased with how Gus and his partner, Max Arciniega (James Martinez), did their business. Hector shot and killed Max, jumpstarting Gus' hatred toward the Salamanca family. More of Hector's backstory was unveiled in Better Call Saul flashbacks, filling in the gaps of the drug kingpin's earlier life.
In the mid-'90s, Hector decided to expand the Salamanca drug reach into the United States by using an ice cream shop as a front. Don Eladio wasn't impressed and it made matters worse when Hector found out that Gus was growing closer to the cartel boss. Gus was clearly trying to edge out Hector but Don Eladio was blind to the man's ulterior motives.
Hector was present in Better Call Saul's primary timeline beginning in season 2. After Tuco was arrested for assaulting Mike Ehrmantraut (Jonathan Banks), Hector tried to smooth things over. He offered Mike money to change his testimony in order to reduce Tuco's charges. Mike initially refused even after Hector sent his henchman to intimidate him. The situation changed when the Cousins were sent to threaten the life of Mike's young granddaughter. Mike then accepted Hector's request but bumped the payout to $50,000.
As an act of revenge, Mike attacked one of the ice cream trucks that was delivering money to Hector across the border. He also whipped up a plan to assassinate Hector but his plan is thwarted by Gus. Hector and Gus were still at odds and the latter had intentions of taking over the control of the drugs crossing the border. As Hector was focused on his feud with Gus, he didn't realize that one of his closest allies was becoming a major threat.
Hector needed a new endeavor to serve as a front for his drug operations so he set his sights on Nacho's (Michael Mando) father who ran an upholstery business. Nacho wasn't pleased with the idea so he stole some of Hector's heart medication. He emptied the pill capsules and refilled them with ibuprofen, which could increase the risk of a heart attack or stroke. The spiked pills finally worked during a drug cartel meeting. Hector suffered a stroke but Gus saved him by using CPR.
In Better Call Saul season 4, Gus hired a specialist from Johns-Hopkins to care for Hector. After learning that Hector could potentially walk and speak again, he discontinued Hector's therapy to trap him in his current state. Nacho was also forced into working for Gus as he was aware of his attempt to kill Hector. With nobody to care for Hector, he was sent to the nursing home, Casa Tranquila. This is where he received the bell which he would use as his main form of communication as seen in Breaking Bad. It's very likely that Hector will reappear in Better Call Saul season 5 when it returns for in 2020.