The introduction of an alternate universe version of Sarek in Star Trek: Discovery wasn’t cool only because Mirror Sarek and Mirror Spock have little beards. There were actually two deeper references here, both of which connect to the original Star Trek canon.
Spoilers for Star Trek: Discovery season 1, episode 11, “The Wolf Inside.”
In the new episode, we learn that in the Mirror Universe, Sarek is one of the good guys, working for a renegade coalition of aliens fighting against the oppressive Terran Empire. From a chronological standpoint, this is interesting because we know that Spock — Sarek’s son — in this universe is totally a member of the Terran Empire. So, just like in the Prime Universe, Spock clearly rejected his father’s wishes here, too. In the “good” Star Trek timeline, Spock joining Starfleet pisses his father off, for a variety of reasons, some of which have been given new layers on Star Trek: Discovery. But, it seems like the beef between Mirror Sarek and Mirror Spock is way worse, for the obvious reason that Starfleet in this dimension is a gang of space Nazis.
In other words, Spock and Sarek’s estrangement in “our” universe seems really petty when you consider how bad it is in the Mirror Universe. In the regular timeline, Sarek and Spock aren’t on speaking terms because Spock didn’t go to his father’s favorite college, the Vulcan Science Academy. In the Mirror Universe, it’s because Spock became a fascist.
Mirror Sarek’s introduction in “The Wolf Inside,” references the original series in another way, too. In order to determine that Burnham’s intentions are pure, Mirror Voq has Mirror Sarek mind-meld with her. This is exactly what happens in “Mirror, Mirror,” when Mirror Spock wants to figure out what is going on with the errant behavior of Bones, Scotty, Kirk, and Uhura. After his mind-meld with Bones, Mirror Spock realizes that these people are not from his universe. In both storylines, a mind-meld allows the good guys to gain sympathy from people in the Mirror Universe. And, ironically or not, the two guys performing these generosity-inducing mind-melds are father and son.
Star Trek: Discovery airs its remaining four episodes of its first season over the next four Sundays. Each episode will air on Sunday night at 8:30 pm eastern time on CBS All-Access.