Elias Toufexis played Cold in the Star Trek: Discovery episode "Context Is for Kings." The Canadian actor has performed on stage, in films and video games, and on television, and is also both a voiceover artist and motion-capture veteran actor. His counts among his credits Decoys, Da Vinci's Inquest, Stargate: Atlantis, Smallville, Supernatural, Splinter Cell: Blacklist, Bitten, Lenand Company, The Expanse and The Long Dark.
Lt. Commander Paul Stamets is the U.S.S. Discovery’s science officer and chief engineer, and was the partner of the late Dr. Hugh Culber. Brilliant, awkward, outspoken and not keen to make friends, his expertise is astromycology, meaning he knows more than anyone about space mushrooms and the vegetative part of a fungus called mycelium. Stamets collaborated with Lt. Straal, conducting research to "get to the living heart of the universe, the veins and muscles that hold our galaxies together." However, the Federation co-opted their research at the start of the Klingon-Federation War in order to develop an organic-propulsion system. Stamets was assigned to the Discovery, while Staal was assigned to the U.S.S. Glenn in order to expedite their research.
Captain Lorca of the Discovery saw in their research the possibility of jumping through space at unimaginable speeds. Though he professed to pushing Stamets and Staal so hard in order to defeat the Klingons, his ulterior motive was to return to the Terran Universe and overthrow Emperor Georgiou. Staal, believing he’d made progress, tested the drive, but died along with everyone else on the Glenn. Stamets forged on, impatiently working with Cadet Tilly. Eventually, they harnessed the spore drive, with Stamets plugging into it as an organic navigator. The drive worked, and Lorca took advantage of it, giving the Klingons a run for their money and getting closer to home.
However, the jumps took their toll on Stamets, leaving him catatonic, but functioning within the mycelial network. When the Discovery crossed into the Mirror Universe, Stamets and Mirror Stamets came face to face, and Stamets was able to say goodbye to Dr. Culber, who'd been killed by Ash Tyler. Tilly soon revived Stamets, who then helped destroy the I.S.S. Charon and guide the Discovery back to the Prime Universe.
For his efforts, Stamets received the Starfleet Medal of Honor and a promotion to Lt. Commander. He also accepted the Starfleet Medal of Honor on Dr. Culber’s behalf.
An astromycologist conducting research with Paul Stamets to "get to the living heart of the universe. The veins and muscles that hold our galaxies together." The Federation co-opted their research at the start of the Klingon-Federation War in order to develop an organic-propulsion system. Staal was assigned to the U.S.S. Glenn as a Science Officer while Stamets was assigned to the U.S.S. Discovery to expedite their research. Straal was killed, along with the entire crew of the U.S.S. Glenn, during black alert manuevers testing the new propulsion system.
Jason Isaacs plays Captain Gabriel Lorca, captain of the U.S.S. Discovery, on Star Trek: Discovery. The veteran British actor’s career spans nearly 30 years and counting, and his credits include Capitol City, Event Horizon, The Patriot, several Harry Potter films (in which he portrayed Lucius Malfoy, the father of Draco Malfoy), Awake, the Rosemary’s Baby miniseries with Zoe Saldana, Dig and Star Wars Rebels.
Isaacs' current and upcoming projects include The OA, London Fields, Behind the Glass, The Death of Stalin and Hotel Mumbai.
Grace Lynn Kung played the prisoner Psycho in the Star Trek: Discovery episode, "Context Is for Kings." A Canadian actress who splits her time between North America and the U.K., Kung counts among her film and television credits Blue State, House Party, Degrassi: The Next Generation, The Strain, Miss Sloane, Mary Kills People, Designated Survivor, Cult of Chucky, Carmilla and Fahrenheit 451.
Mary Wiseman stars on Star Trek: Discovery as Sylvia Tilly, a Starfleet Academy cadet in her final year of study, assigned to the U.S.S. Discovery.
The young actress, who studied at Juilliard, counts among her credits episodes of such TV series as The Characters, Difficult People, Longmire and Baskets. Her stage work includes an off-Broadway production of The Octoroon, as well as her 2015 Broadway debut in Therese Raquin and a 2017 production of The Skin of Our Teeth at the Theater for a New Audience in Brooklyn, New York.
Toronto native Ronnie Rowe played a Shuttle Pilot in the Star Trek: Discovery episode "Context Is for Kings" and a communications specialist in "Magic to Make the Sanest Man Go Mad." His prior credits include Warehouse 13, Saving Hope, Dark Matter, The Expanse and the film, Black Cop.
Devon MacDonald portrayed an Engineering Officer in the Star Trek: Discovery episode "Context Is for Kings." Among her other credits are The Best Years, Breakout Kings, Lost Girl, Tru Love and Covert Affairs.
Julianne Grossman, who provides the voice of the U.S.S. Discovery’s computer, is an actress, standup comic and veteran voiceover artist. Her many credits include Doubt, Spaceballs: The Animated Series, The Life & Times of Tim; Superman/Batman: Apocalypse, Wonder Woman, Justice League, and Rugrats: All Growed Up; campaigns for Target, Visa, McDonald's, Honda, Nike, Appleby's, and many more; promos for CBS, ABC, NBC, FOX, PBS, HGTV, TLC and HBO; and narrating duties on behalf of "E," The Style Channel, The Travel Channel, HGTV, Discovery, etc.
Grossman, who hails from Los Angeles, has also lent her voice to numerous videogames, including Elder Scrolls, Star Wars: The Old Republic, X-men: Next Dimension, Everquest, Infamous, God of War II and DropZone. Her solo show and playwriting debut, From Bonkers to Botox, enjoyed a 9-week sold-out run in Los Angeles and was selected by HBO as a Featured Performance in their U.S. Comedy Arts Festival.
Saad Siddiqui played Straal, Lt. Stamets' doomed research partner, in the Star Trek: Discovery episode, "Context Is for Kings." Born in Pakistan and raised in Maryland, Siddiqui is an actor and world-class martial artist. Among his dozens of film and television credits are Warehouse 13, Unnatural History, Cosmopolis, Rogue, Orphan Black, 24: Legacy, Taken and Fahrenheit 451.