To the best of my knowledge the (in-universe) explanation for why the Klingons didn't have cranial ridges in TOS was because of a genetic disease caused by attempts to manipulate Klingon DNA to create augments (like Khan):

In the year 2154, the Klingons gained access to the genetic material of Human Augments and tried to adapt this genetic engineering to improve themselves.... One of the subjects suffered from the Levodian flu, which was modified by the Augment DNA to become a fatal, airborne, mutagenic plague that spread rampantly through the Empire, from world to world. In the first stage of this plague, Klingons lost the ridges on their foreheads

However, I recall seeing in the episode chain of Enterprise where the Klingons became infected with the virus, that the augmented children that the Klingons based their research on were augments from Khan's folk.

The scientist who leads the augments is Dr. Arik Soong (an ancestor of Dr. Noonian Soong, Data's father). Now if these children were augments then, in the prime timeline, Dr. Arik Soong likely found them aboard the Botany Bay and took them for safe keeping. However in the Abramsverse the Augments are likely under section 31's control and so would be kept under guard on earth, meaning that the Klingons wouldn't experiment with genetic research. Therefore everything is fine then? No.

Because the Augment virus ravaged the Klingon population prior to the U.S.S Kelvin's fateful encounter with Nero, then the Klingons (or the majority of them) should still have disease-ravaged heads in Into Darkness.

So how/why exactly do the Klingons in Into Darkness have cranial ridges?

  • “possibly an ancestor of Dr Singh, Data's father” — you may be thinking of Doctor Soong, whose first name was Noonian (note the different spelling to Khan Noonien Singh). Commented Feb 15, 2016 at 23:19
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    Ah sorry haven't watched TNG in a while. PS to whoever edited the post thank you very much, I apoligise for the grammer being terrible earlier (first post)
    – user62054
    Commented Feb 15, 2016 at 23:21
  • that’s quite alright. That was me editing the post too, and naw, your meaning was very clear. (I’m just a bit obsessive with edits.) Commented Feb 15, 2016 at 23:22
  • @Kor : You're welcome. :-)
    – Praxis
    Commented Feb 15, 2016 at 23:25
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    @T-1000'sSon : The augment virus occurred before the two timelines diverged.
    – Praxis
    Commented Feb 16, 2016 at 1:34

4 Answers 4


There were ridged (uninfected) Klingons, but the appearance of ridged Klingons in Into Darkness was a conscious retcon.

Many millions — but not all — of Klingons were infected by the augment virus (ENT "Divergence"), and so a reasonable (but unconfirmed) in-universe theory would be that the Klingons in Into Darkness were descendants of those who were not infected.

ANTAAK: I suppose this is what I deserve. Millions of my people will have to live with this disfigurement. It'll be passed on to our children. Life won't be easy for us.

The words of the Klingon scientist Antaak imply that not everyone was infected. Also, we should take into account that we had never seen Qo'noS in TOS. The Klingons in Into Darkness were encountered on the homeworld itself, where one expects to find a greater diversity of Klingons.

All of that being said, one of the film's writers, Bob Orci, used to frequent the TrekMovie news site (before he famously lost his cool with Star Trek fans). In the lead-up to Into Darkness, he said

  1. boborci - June 3, 2012

So in our universe, they still have ridges, whether they are in the sequel or not;)


I interpret this as saying that they were explicitly retconning ridge-less Klingons from TOS and the genetic augment virus from Enterprise.

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    "before he famously lost his cool with Star Trek fans" sounds interesting. details.:)
    – RedCaio
    Commented Aug 2, 2016 at 19:17
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    @RedCaio : He wasn't happy that Star Trek fans weren't pleased with Into Darkness. He said bad things on the Internet about them.
    – Praxis
    Commented Aug 2, 2016 at 21:07

Another explanation: Recall that Antaak's last words in that episode expressed the thought that 'now might be a good time to make a career-move into doing reconstructive plastic surgery'.

  • Could you elaborate on this?
    – Adamant
    Commented Aug 2, 2016 at 17:31
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    @Adamant: Seems pretty self-explanatory. It was an indication that at least one Klingon thought other Klingons may want to hide the effects of the virus with plastic surgery. It's not proof that anyone actually went for it, but it does make a valuable suggestion as to where these ridgy Klingons may have come from. Commented Aug 2, 2016 at 18:04
  • There is strong evidence that some of them did go for it (namely, Klingons who show up in TOS without ridges and in DS9 with ridges).
    – Micah
    Commented Mar 18, 2018 at 14:01

I haven’t seen the Enterprise episodes in question, but was far as I can tell, it isn’t stated that every Klingon lost their cranial ridges to the disease, and Dr. Phlox did develop a cure for the affliction during the Enterprise episodes in question.

Thus I’d assume that the few Klingons we saw in Into Darkness didn’t have the disease, and their ancestors either didn’t have it, or did, but got cured.

The galaxy is big, and full of Klingons.


This is a late response but the reason is that this is a different reality. When Nero made his incursion into the past he created a new reality that was changed from the top to bottom. (Google Simon Peggs comments). The Augment virus didn't happen in their reality. By now if you have seen Star Trek Discovery, it is clear that the timelines are different. The only tie it has to the original universe is that two beings from that universe altered it.

  • Can you provide the links to Simon Pegg’s comments in your answer? Or possibly a quotation that supports your answer?
    – Edlothiad
    Commented Mar 18, 2018 at 13:15

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