The series finale of Chilling Adventures of Sabrina left a lot of questions behind, but one of the more perplexing is what happened to the Endless version of Salem the cat? After Netflix cancelled Chilling Adventures of Sabrina in July 2020, the show came to a close with season 4, which released on the streamer on December 31, 2020. While perhaps not how things would’ve wrapped up had it not been cancelled, it did give endings to its key characters, in particular the two Sabrinas, Spellman and Morningstar.
Both of their journeys came to a close in Chilling Adventures of Sabrina season 4, episode 8, “Chapter 36: At the Mountains of Madness.” In the end, both Sabrinas died, but neither without confusion. There are questions as to why Sabrina Spellman couldn’t be brought back, and Morningstar’s death is also mysterious. Having been sent to an alternate reality, she crashed back through the mirror into the real world, warning of the eighth and final Eldtritch Terror, the Void. This killed Sabrina, perhaps from injuries off the mirror or relating to the terrors, but she wasn’t the only one to make the trip.
Sabrina crashed through the mirror with the version of Salem who was running things in the alt-dimension (which riffed on the Sabrina the Teenage Witch sitcom, including making Salem the true star). Unlike the real Salem, this cat could talk and, more importantly, was an Eldritch Terror himself: the Endless. However, even though Sabrina Morningstar had been holding him, Salem isn't shown again on screen, suggesting he somehow vanished. There’s no clue as to what happened to him, nor even a mention of the fact he disappeared. It was simply as though he’d never even been there at all.
The most likely answer is that, as with Sabrina Morningstar, Endless Salem was killed when journeying through the mirror portal, either as a result of the sheer force it takes travelling between dimensions or from being touched by the Void (which had been closing in), or perhaps a combination of the two. As a Terror, he should have been able to survive the journey, but the Void was at least shown to be all powerful and all consuming, so would be more believable. With that, then, it’s possible Salem was simply sucked into the Void the way other objects do, like when part of it is inside Sabrina.
This explanation would make some sense, but isn’t wholly satisfying. It doesn’t account for the fact they had seemingly (if briefly) escaped the Void, or why nothing is shown for what happens to Salem. With the Eldritch Terrors all defeated by the end of Chilling Adventures of Sabrina then there’s no room to further explore what happened to the talking Salem, and so the mystery will remain endless.