WARNING: Spoilers for Star Trek: Discovery season 2, episode 4.

Star Trek: Discovery's Saru now rivals Spock as the franchise's best alien character. Star Trek has always been about seeking out new lifeforms and has introduced beloved aliens like the Klingon Worf, Quark, Rom, and Nog's Ferengi family, Odo the changeling, and the android Data.

In Star Trek: Discovery season 2, episode 4 "An Obol for Charon", Saru (and Doug Jones, who portrays him) broke fans' hearts when he revealed he was dying. An encounter with an alien sphere triggered the Vahar'ai, the Kelpien biological process that leads to death. On their homeworld Kaminar, the Kelpien race exists in a binary society with a mechanical species called the Ba'ul. The Kelpien are prey whose existence serves to benefit their Ba'ul predators and their entire society is structured around fear, submission, and acceptance of being sacrificed to the Ba'ul - this is called the Great Balance and it's all the agrarian Kelpien society know.

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With the Vahar'ai in effect, Saru believed his condition was terminal. The Kelpien undergo the Vaharai right before they are sacrificed and killed by the Ba'ul; to refuse to submit means undergoing madness that leads to death anyway. Like all Kelpiens, this is what Saru knew of his species - but he learned how all of this was a lie and this changes everything about Saru for the better.

Saru's Life Was Completely Different Before He Joined Starfleet

In the Short Trek episode "The Brightest Star", fans learned how Saru dreamed of more than the sad existence of the Kelpiens, whose lives are sacrificed to the Ba'ul. Saru lived a simple farming life with his sister Siranna and their father Aradar, who was a priest. Despite Aradar stifling his natural curiosity, Saru repaired a Ba'ul communication device and sent a signal into space. It was answered by Starfleet's Lieutenant Philippa Georgiou, who arrived on Kaminar and offered Saru the chance to join Starfleet. However, because Kaminar is a pre-warp civilization, it was subject to General Order One (the Prime Directive). This means the Kelpiens can never know Starfleet exists and leaving would mean Saru can never return home. Saru boldly chose to experience a new life and find his destiny among the stars.

In "An Obol for Charon", Saru learned that the Kelpien don't die from the Vahar'ai - instead, when their fear ganglia fall out, his race loses their fear entirely. The Ba'ul created a lie to maintain the Kelpiens' fear and submission, which the entire Kelpien society is based around. Now, Saru not only remains the deeply empathic, intelligent, and compassionate soul he always was, but he is no longer crippled by fear (this was alluded to in the season 1 episode "Si Vis Pacem, Para Bellum" when Saru was able to experience not feeling fear on the planet Pahvo). Saru has emerged stronger and braver than ever; the First Officer is living proof of what Kelpiens are meant to become if they only knew the truth.

How Star Trek: Discovery Season 2 Made Saru The Best Alien Character

Already a fan favorite, Saru has evolved into a brilliant and inspiring Acting Captain who led the Discovery through the Mirror Universe and past the betrayal of Captain Gabriel Lorca. The Kelpien overcame his grudge against Michael Burnham for her mutiny and gave her the opportunity she needed to redeem herself and earn back his trust; now, they're as close as family. Saru's death scene with Michael wasn't just heart-wrenching, it powerfully echoed Spock and Kirk when the Vulcan died in Star Trek II: The Wrath of Khan.

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Saru also proved himself to be a caring mentor to Ensign Sylvia Tilly, taking a special interest in her and encouraging her efforts in Starfleet's Command Training Program. Even more impressive, Saru speaks 94 languages and has no need for a universal translator. When Saru told Michael the story of his first arrival at a Starbase and meeting myriad alien species for the first time, it was a parable of an immigrant who dreams of a better life, works hard to achieve his dreams, and then gives back to society.

Star Trek's aliens often mirror our very human struggles, starting with Spock trying to balance his humanity with his emotionless Vulcan logic. However, Spock is half-human; Saru is a very alien being who comes from a society unlike our own, yet he has become arguably the most compelling character on Star Trek: Discovery. Saru is a loyal, empathic friend, a heroic Starfleet Officer, and he shows how anyone can overcome the limitations of their upbringing to evolve into something more and better. It will be fascinating when Saru and Spock, Star Trek's two best alien characters, finally meet in Star Trek: Discovery season 2.

Next: Star Trek: Discovery Explains Why Spock Kept Michael Burnham A Secret

Star Trek: Discovery streams Thursdays at 8:30pm on CBS All-Access and the next day internationally on Netflix.