Summary

• Captain Rayner from Star Trek: Discovery is revealed to be a Kellerun, not Vulcan or Romulan.
• The Kellerun species was first seen in Star Trek: Deep Space Nine season 2.
• Trek Central tweeted about Michelle Paradise confirming Callum Keith Rennie as a Kellerun in SFX Magazine.

Star Trek: Discovery showrunner Michelle Paradise has revealed the surprising alien species season 5's new Starfleet character, Captain Rayner (Callum Keith Rennie), belongs to. From the early images and Discovery season 5 trailers, it initially appeared that, with his pointed ears, Rayner may be a Vulcan or Romulan. However, the final Star Trek: Discovery season 5 trailer showed Rayner snarling with rage, heavily implying that he wasn't an emotionally repressed Vulcan.

In an interview with Star Trek: Discovery's Captain Rayner is not a Vulcan, nor is he a Romulan. Instead, Rayner is a member of the Kellerun species, first seen in Star Trek: Deep Space Nine season 2, episode 13, "Armageddon Game". Trek Central tweeted the news, complete with an image of a Kellerun from DS9's "Armageddon Game". Read their tweet below:

UPDATE: TrekMovie spoke to Star Trek: Discovery showrunner Michelle Paradise at SXSW and got more information about Captain Rayner as a Kellerun. Read her quote below:

[Captain Rayner is] a Kellerun. We were looking for a species that not a lot had been done with them. We definitely wanted another non-human on the ship and taking care of things. And Kellerun is one that had not been explored a whole lot. So we were able to also build some backstory for him and for his planet that we’ll come to learn more about later.

Kellerun Species In Star Trek: DS9 Explained

The Kellerun only appeared in one episode of Star Trek: Deep Space Nine, "Armageddon Game". A species that hailed from the Gamma Quadrant, the Kellerun were encountered by Chief Miles O'Brien (Colm Meaney) and Dr. Julian Bashir (Alexander Siddig) at the end of a brutal war with the T'Lani. O'Brien and Bashir were dispatched to help with destroying the final traces of a biological weapon known as the Harvester. Sharat (Peter White), a Kellerun ambassador, sought to secure lasting peace by erasing all knowledge of the weapon by killing everyone involved with it, including Bashir and O'Brien.

Their encounter with the Kellerun was a crucial moment for Chief O'Brien and Dr. Bashir's friendship, establishing the bond between them. Sharat's single-minded desire to erase all knowledge of the Harvester in Star Trek: Deep Space Nine could have interesting implications for Captain Rayner. From the clips released from Star Trek: Discovery season 5, Rayner seems similarly single-minded, nearly killing Captain Michael Burnham (Sonequa Martin-Green) and his own crew in pursuit of the villainous Moll (Eve Harlow) and L'ak (Elias Toufexis). Scorched Earth policies are clearly a Kellerun trait, which could set up a fascinating dynamic between Rayner and Burnham in Star Trek: Discovery season 5.

Star Trek: Discovery and Star Trek: Deep Space Nine are available to stream on Paramount+.

Sources: SFX Magazine, Trek Central, TrekMovie.com