(Warning: The following contains spoilers for the Season 3 finale of Better Call Saul.)

Before Season 3 of Better Call Saul premiered, Michael McKean warned us not to get too attached to his character Chuck McGill, the brilliant but mentally ill — and unrelentingly cruel — older brother of Jimmy McGill (Bob Odenkirk). It was an interesting choice of words to use about such an unlikeable character, and yet Chuck's implied death in the Season 3 finale was heartbreaking.

The exceptional writing and McKean's remarkable performance worked in tandem to make the audience see Chuck as the human tragedy he is, and by the end, we felt bad for a man who has said and done many horrible things over the course of the show's three seasons. But McKean is humble about the craft that went into making Chuck into such a complex figure. "As an actor I just tried to make him a real guy with more than one side to him," he tells TVGuide.com.

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At the beginning of the finale, Chuck — despite being the healthiest he's been in years, thanks to psychiatric treatment he's finally getting — is definitively forced out of the law firm he co-founded by his partner Howard Hamlin (Patrick Fabian), who buys out Chuck's shares with his own money to protect the firm from Chuck's lawsuit over malpractice insurance. The firm — and the hope of one day practicing law again — was the only thing Chuck still had after he drove away his family. And when Jimmy comes to see him to express remorse for humiliating him in the courtroom in "Chicanery," Chuck tells him not to bother. He tells Jimmy he is not going to change, he's just going to keep on hurting people, so his remorse doesn't matter, and besides, Chuck's over it. The last words Chuck ever speaks to his brother are "I don't want to hurt your feelings, but the truth is you've never mattered that much to me."

Michael McKean, <em>Better Call Saul</em>Michael McKean, Better Call Saul

That night, Chuck relapses back into his psychosomatic electromagnetic sensitivity and turns the power off in his house. But the electric meter is still spinning, so he tears his house apart looking for the buzz. By the end of the hour, he's sitting alone with all the holes he'd made in his walls, finally taking stock of the mess he's made of his life, and decides to end it by knocking a kerosene lantern off a table onto the floor.

As for what it was that finally pushed Chuck over the edge, McKean says there wasn't any single thing. "His edges have been so rounded that it's hard to say where the edge is," he says. "In other words it's more of a slope." Each humiliation or loss of his heart pushed him a little further down the slope, and when he finally reached the bottom, he saw no way back up. "The prospect of not having to go through this or anything else again becomes attractive," he says.

Since the dissolution of Chuck and Jimmy's relationship has always clearly been one of the things that pushed Jimmy McGill into becoming Saul Goodman — and since Chuck doesn't appear in Breaking Bad -- McKean says he always recognized that Chuck's death was a possibility as a mechanism to make that happen, noting though that death is always a possibility on serial television. Still, "it was painless as far as I'm concerned," McKean says, "because I like a good story and I think this made the story really good."

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In the wake of the events of the Season 3 finale, McKean says he'll go back to being a fan of Vince Gilligan and Peter Gould's work (he's very excited about the Jonestown miniseries Gilligan is developing for HBO), but he also still has to catch up on Better Call Saul — he's only seen the first five episodes of Season 3 and the eighth episode, "Slip."

As for what he'd like to see next season on Better Call Saul (the series has not yet been renewed, but it almost certainly will be), McKean is looking forward to the things most fans are excited about. In addition to the increasingly "hot and heavy" crime element with Mike (Jonathan Banks), Nacho (Michael Mando) and Gus Fring (Giancarlo Esposito), he is excited to see Kim's story evolve. "I wanna see Kim outgrow her own limitations," he says. "She's such a great character and [Rhea Seehorn is] such a great actress."

"We know Jimmy's target," he continues. "We know where he's heading. But Kim is still a mystery to us, and she's so smart and she potentially has such a great heart. She doesn't let herself own herself yet. But she's beginning to."