[Warning: This post contains spoilers from Episode 13 of Star Trek: Discovery, "What's Past Is Prologue." Read at your own risk.]

It's the end of the line for Gabriel Lorca (Jason Isaacs) on Star Trek: Discovery. Well, the Mirror Universe version of him anyway.

The malevolent captain nearly reached his goal of overthrowing Emperor Georgiou (Michelle Yeoh) only to be killed by her following an intense hand-to-hand battle in Sunday's jaw-dropping episode. While other versions of the character mostly likely exist — namely Prime Universe Lorca whose fate has not yet been revealed — Mirror Universe Lorca's story has officially come to a close on the sci-fi series.

"He had some grand plans and came very, very close to pulling them off and now it's all over," Jason Isaacs tells TV Guide.

Lorca's death also marks the end of a complicated relationship with Michael Burnham (Sonequa Martin-Green), who he manipulated in order to find his way back to the Mirror Universe. Despite forging a special bond with her strictly for his benefit, Isaacs says Lorca's ploy to gain her trust was an act of necessity rather than malice.

"In his mind, he didn't betray her. He did what was necessary," Isaacs explained.

Star Trek: Discovery: Lorca's Shocking Reveal Is Bad News for Everyone Else

The episode saw Lorca offer Burnham a chance to join him and rule the Terrans side-by-side just as he planned with her Mirror Universe counterpart. Burnham, having no interest in becoming an evil ruler, sided with Emperor Georgiou instead. "He thinks that maybe she will see the good sense in staying by his side and it looks for a moment like she will. She plays on that very smartly," said Isaacs.

With Lorca intent on taking out Georgiou and Burnham equally determined to stop him from doing so, the two were at a crossroads which meant Lorca would have to put her down as well. It's an option that, according to Isaacs, he wasn't exactly thrilled with.

"He doesn't want to have to kill her," he said of Lorca's dilemma. "But the fact is [Lorca's] probably too confused with Mirror Burnham who subscribed to the same kind of racist hierarchal belief [of dominion over the other races] that [Mirrorverse Lorca has] and she's never gonna go for that."

While Burnham did end up rejecting Lorca's plan, she still couldn't bring herself to end his life when the opportunity presented itself.

" I think it's fitting that she didn't kill him because she didn't really want to. She's confused by her relationship with him," added Isaacs. "She's also our hero and she makes very moral choices all the time. Whereas Emporer Georgiou is a very immoral creature and she does what's necessary."

And Georgiou's necessary action meant Burnham could move forward with a clear conscious.

New episodes of Star Trek: Discovery stream Sundays at 8:30/7:30c exclusively on CBS All Access.

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Jason Isaacs, Star Trek: DiscoveryJason Isaacs, Star Trek: Discovery