Summary
WhenStar Trek: Discoverypremiered in 2017, the Trek fandom collectively lost its mind over many aspects of the show. In particular, they had a big problem with theappearance of the Klingons. They looked very different than they had in any other show in the franchise, andStar Trekfans were not pleased.
This wasn’t the first time the overall look of theKlingons was redesigned, but their appearance had remained relatively consistent sinceStar Trek: The Motion Picturewas released in 1979. UntilDiscovery, the only time the Klingons' appearance had significantly changed since 1979 was whenStar Trek: Enterpriseintroduced the Augment Klingons, a storyline that was written to explain why the Klingons fromThe Original Serieslooked so different from the Klingons in theStar Trekmovies and subsequent shows.

Discovery’swriters never introduced an in-universe reason why their Klingons looked so different, but in an interview with SFX Magazine, excerpted byTrekMovie.com, one of the executive producers explained that these Klingons were an ancient sect, isolated from the rest ofKlingon society, that evolved differently from other Klingons. Alex Kurtzman, another executive producer on the show, has repeatedly stated (as he did in an interview withCinemaBlend) that just as there are wide variations in the way humans look, there are wide variations in the way Klingons look.
Given these explanations, most fans grudgingly accepted thatDiscovery’sKlingons were just a natural variation of Klingons. However, the events in the series finale ofStar Trek: Lower Decksoffer another potential explanation for whyDiscovery’sKlingons are so different from their brethren.

DiscoveryKlingons inLower Decks
In “The New Next Generation,” the final episode ofLower Decks, the crew of the U.S.S. Cerritos is trying to clean up the mess made byLily Sloane’s quantum reality drive ship. The quantum rift that Lieutenant Harry Kim opened to try and return to his own universe in the previous episode, “Fissure Quest,” is overloaded with soliton resonance, which threatens to destroy the Prime Universe. The crew of the Cerritos has to close the rift ASAP.
Unfortunately, the rift is surrounded by a Schrödinger Possibility Field. As Starfleet Command explains to the Cerritos' bridge crew, this is a brand-new phenomenon in their quantum reality. The field actually rearranges matter, transforming lifeforms into versions of their species that exist in other quantum realities. For example, if there’s a quantum universe where humans still have tails, the Cerritos crew members could find themselves with tails. Or countless other weird configurations.

The geniuses of the Cerritos' Engineering department develop a shield that will protect them from the changes. But when aKlingon shipwithout the shield modifications enters the Schrödinger Possibility Field, the crew morphs into different alternate versions of Klingons, including aDiscovery-style Klingon.
Alternate Reality Klingons?
The inclusion of aDiscoveryKlingon in theLower Decksfinalecould be a simple Easter egg. Or it could finally provide a solid in-universe explanation for whyDiscovery’sKlingons look so different from all the other Klingons in the Prime Universe.
The Schrödinger Possibility Field transforms lifeforms into different versions of the same species that exist in other quantum realities. Since one of the Klingons turned into aDiscovery-style Klingon, this confirms that Klingons who look like that exist in other quantum realities. This introduces the possiblity thatDiscovery’sKlingons were never actually from thePrime Universe.

At some point in the Prime Universe’s past, Klingons from a different quantum reality could have crossed over into the Prime Universe.Star Trek’scanon has repeatedly established that there are multiple realities and timelines, and that lifeforms move between them all the time. Maybe the alternate universe Klingons developed a quantum reality drive, like Lilly Sloane and Zefram Cochrane did in another quantum reality, and they traveled to the Prime Universe. Or maybe they ended up there throughsome weird rift. It’sStar Trek. Pretty much anything can happen.
How it Fits WithDiscoveryCanon
The appearance ofDiscovery’sKlingons wasn’t the only thing that was different about them. Their culture, religion, and customs were all different as well. ThoughDiscovery’sEP explained this by saying they were an ancient sect that followed earlyKlingon religious and cultural practices, it would make a lot of sense for them to be so different if they literally had a different history than the Prime Universe Klingons.
Star Trekcanon has also established that some realities are so similar to each other, that they’re almost indistinguishable. So, it’s hardly a stretch to believe that in an alternate reality,Kahless still existed, but his legacy was interpreted differently and formed into a different basis for Klingon religion and culture.

Before the objections start rolling in, yes, some ofDiscovery’sKlingons did live on thePrime Universe’s version of Qo’noS, andDiscoverydidn’t show any traditional Prime Universe Klingons on Qo’noS. This kind of made it seem likeDiscovery’sredesigned Klingons were the only Klingons on the planet. However, Qo’noS is a huge planet. It’s plausible that the small sect ofDiscoveryKlingons lived in one village, while the rest of the Prime Universe Klingons lived on other parts of the planet.
In fact,Strange New Worldsseems to confirm that theDiscoveryKlingons and the Prime Universe Klingons co-existed. Just a few years after the events depicted in the first two seasons ofDiscovery, which only involvedDiscovery-style Klingons, the crew of the U.S.S. Enterprise encountered Klingons inStrange New Worlds. Those Klingons looked like the Klingons in every post-TOSmovie and show.
Strange New Worldsconveniently didn’t mention that at leastCaptain Christopher Pike, First Officer Una Chin-Riley, and Lieutenant Spock had seen Klingons who looked very different from the ones they encountered in their later travels. However, this actually makes the coexistence ofDiscoveryKlingons and Prime Universe Klingons more believable. The Enterprise crew members were used to seeing different versions of Klingons, so they weren’t confused when they encountered Klingons who looked very different from the ones they’d dealt with before.
GivenLower Decks’confirmation thatDiscovery-style Klingons exist in other quantum realities, it’s completely plausible, if not probable, thatDiscovery’sKlingons are actually Klingons from another quantum reality that settled in the Prime Universe and existed alongside Prime Universe Klingons. Whether or not theLower Deckswriters intended to give an in-universe explanation of whyDiscovery’sKlingons looked so different, they have created an interesting, and canon-based, reason for one of theStar Trekuniverse’s biggest plot holes.
Sources:CinemaBlend,TrekMovie.com,Star Trek: Discovery, Star Trek: Strange New Worlds, Star Trek: Lower Decks