Star Trek: Discovery jumped into the Mirror Universe to launch the second half of season 1 and discovered a dark mirror of the Prime Universe where black is white and good is evil. In the Mirror Universe, the benevolent United Federation of Planets we've come to know has a fascistic, militaristic counterpart: the Terran Empire, which has conquered known space with its Starfleet. The Empire is ruled, unsurprisingly, by a mysterious Emperor.
Whenever a Star Trek series ventures into the Mirror Universe, the mirror opposites of that series' characters tend to play significant roles in the overall events of the Mirror Universe. This began all the way back in The Original Series, when the Mirror Spock (rocking his famed goatee) changed his sadistic ways after encountering the Prime universe's Captain Kirk. Eventually, Spock became the Commander-In-Chief of the Terran Empire and implemented new reforms that made the Empire a more peaceful galactic power. However, as seen in Star Trek: Deep Space Nine, this ultimately led to the Empire being overthrown by the Klingon-Cardassian Alliance, which was ruled by Regent Worf.
Related: The Mirror Universe Explained
According to Star Trek tradition, it's very likely the mirror version of one of Discovery's characters will turn out to be the Emperor. We already know from the Jonathan Frakes-directed episode 'Despite Yourself' it's not Michael Burnham, whose mirror opposite is Captain of the ISS Shenzhou, Captain Lorca, who is pretending to be her prisoner as his double's whereabouts are unknown, or Sylvia Tilly, whose doppelganger is the feared and brutal "Captain Killy" of the ISS Discovery.
We can logically surmise the Emperor will be revealed to be one of the remaining Discovery characters:
The mirror opposite of the late Captain Philippa Georgiou is most fans' prime suspect as the Emperor. In the main universe, Georgiou died at the Battle of the Binary Stars but her influence continues to be felt in the lives of First Officer Saru and Michael Burnham, her mutinous protege. Burnham battled the Klingon leader Kol in the mid-season finale in order to retrieve her former captain's Starfleet badge, which Kol kept as a trophy after Georgiou suffered a grisly fate on board the Klingon Ship of the Dead.
Georgiou is also the top suspect as the Emperor because it remains unfathomable that an actor of Michelle Yeoh's caliber would be utilized by Discovery in such a limited capacity. Emperor Georgiou would be an ideal way to resurrect that character while having Yeoh portray the opposite of the warm, gregarious commander we met in the series premiere. Georgiou as the Emperor would also force Burnham to confront the face of her gravest mistake once more, but under a whole new and more difficult set of circumstances.
If Georgiou is indeed the Emperor, it would also nicely continue a legacy began on Star Trek: Enterprise. Their two-parter in the Mirror Universe ended with Hoshi Sato killing Captain Jonathan Archer and declaring herself Empress. While this took place a century before the events of Star Trek: Discovery, another Asian woman ruling the Terran Empire would fittingly mirror Enterprise.
Discovery took pains to highlight the racist and xenophobic composition of the Terran Empire, yet Enterprise established several aliens were serving in Starfleet and we know that in less than a decade of Discovery's mirror-future, Spock will serve on the ISS Enterprise (he is likely already a crew member). Therefore, despite the war the Terrans are waging against the Vulcans and Andorians, the mysterious Emperor could be a Vulcan himself - Sarek.
It's not illogical to think Sarek would side with the humans over his own people. Sarek has always had a fondness for Earthlings and he is famed for taking the human Amanda Grayson as his wife. Sarek also harbors some resentment towards the Vulcans for how they treated both his biological son Spock and his adopted daughter Michael Burnham when they each applied to the Vulcan Science Academy. Also, Vulcan extremists have already tried to murder Sarek, which may have also been attempted in the Mirror Universe.
Sarek is seen in the teaser for next week's episode also sporting the famous Vulcan facial hair. Could he reveal himself as the Emperor? We may find for Emperor Sarek, the needs of the many of the Terran Empire may outweigh the needs of the Vulcans and other races in the galaxy.
Information about First Officer Saru's mirror self was conspicuously absent from 'Despite Yourself'. Strangely, Saru didn't seem that curious about what his alternate universe doppelganger is up to. It's possible the Mirror Saru overcame all of the fear he lives with as a Kelpian and successfully made the kind of power play our Saru would never attempt: control of the Terran Empire.
This seems far fetched, and it's more likely Saru and the rest of the Kelpians have been victimized by the Empire, but we've seen evidence on Pahvo that Saru can be prone to madness under certain circumstances. We've also witnessed his temper and single mindedness when he temporarily took command of the Discovery while Captain Lorca was imprisoned by the Klingons. The Mirror Universe may shock fans by revealing both the best and worst of Saru as the Emperor.
Harry Mudd may have had the last laugh after all in the Mirror Universe. The intergalactic charlatan and scoundrel as re-imagined by Rainn Wilson is more devious and deadly on Discovery than the classic portrayal of Harry Mudd in The Original Series. The Mirror Universe's Harcourt Fenton Mudd may well be much more successful in his nefarious schemes than our version is.
We know that Mudd has access to alien time travel technology. It stands to reason Mirror Harry would also have the same resources at his disposal, which he could have used to swindle his way into the highest seat of power in the Terran Empire. When he attacked the Discovery and trapped the crew in a time loop, Mudd fancied himself a captain after repeatedly murdering Captain Lorca. However, Mirror Harry could have aimed much higher. We may well have to get used to calling him Emperor Harry Mudd in the Mirror Universe.
Let's not forget the entire Mirror Universe opened up for Discovery when Lt. Paul Stamets plugged himself into the mycelial spore network. Our first foreboding glimpse of the Mirror Universe was Stamets' reflection moving independently of him. In Discovery, Paul Stamets is literally the face of the Mirror Universe. Could he also be the mysterious Emperor?
There has been no mention yet of the Mirror Universe's version of Paul Stamets, but we could have already seen him in the mirror. If the Mirror Stamets has already been exposed to the mycelial network, he may have heightened sensory capabilities that render him as not fully human - which our version of Stamets is still adjusting to. This Mirror Universe madness could all end up being be the work of Emperor Paul Stamets.
Outside chances for the Emperor include Ash Tyler (somehow also surgically altered from his true Klingon form in the Mirror Universe) and even Admiral Cornwell. However, the over-under is strongly leaning towards Emperor Georgiou. So far, Star Trek: Discovery has a habit of presenting a mystery that fan theories easily guess the answer to before the reveal turns out to be that very answer (looking at you, Klingon Ash Tyler!). Yet in Star Trek, "there are always possibilities", and those possibilities are fun to consider.
Who do you think the Emperor will be? Let us know in the comments.
Star Trek: Discovery streams @ 8:30pm ET on CBS All-Access, Space in Canada, and internationally on Netflix.