Saru (portrayed by Doug Jones) is a captain serving as first officer of the USS Discovery, and the first Kelpien to enter Starfleet. Saru was introduced in the series premiere as a lieutenant commander serving as chief science officer on the USS Shenzhou, which is rendered a hulk during a battle in the series' second episode. Before the events of "Context Is for Kings", Saru becomes first officer on the USS Discovery.
In the Star Trek: Short Treks episode "The Brightest Star", it is revealed that Saru adapted a communication device left behind by the pre-warp Kelpien's oppressors (the Ba'ul), eventually connecting with a young Starfleet officer—Lt. Philippa Georgiou—who obtained permission to "rescue" him from his planet.
Jones was cast as Saru in November 2016. Kelpiens, a new species created for Discovery, were hunted as prey on their home planet and thus evolved the ability to sense the coming of death. This skill has given them a reputation for cowardice in the Federation. Jones was excited to, "from the ground up, develop and find this character and his species" and not have to honor a previous fan-favorite representation. He based Saru's walk on that of a supermodel, out of necessity thanks to the boots he had to wear to portray the character's hooved feet forcing Jones to walk on the balls of his feet. The producers compared Saru to the characters Spock and Data from previous series in the franchise.