Seska is a character in Star Trek: Voyager played by Martha Hackett .

This Cardassian undercover agent infiltrated a Maquis cell under the surgically-altered guise of a Bajoran, and spent several months on the starship Voyager after both her Maquis cell and the U.S.S. Voyager were pulled into the Badlands by the mysterious, dying alien entity known as the Caretaker.

During her time with the Maquis, Seska had a love affair with her commander, former Starfleet officer Chakotay, and befriended the half-Klingon, half-human B'Elanna Torres. Seska's former relationship with Chakotay would later prove key to her plan to capture Voyager in "Basics, Pts. 1 & 2 ."

Once aboard Voyager, Seska slowly melded into a normal life with the mixed Starfleet-Maquis crew, a process not without difficulty. Eventually, after several clashes with the ship's rigid command structure and increasing frustration with the command of Captain Kathryn Janeway, Seska detached herself from the rest of the crew and began funneling assistance to the Kazon. She was caught while attempting to deliver transporter technology to the enemy, and upon her apprehension, her true Cardassian identity was discovered by the Doctor. Seska fled to the Kazon whereupon Maje Culluh took her as a lover.

The Kazon were able to capture Voyager with Seska's help after she joined their crew. Seska had impregnated herself with her former lover Chakotay's DNA and used the child as bait, knowing Chakotay would never abandon the child to the Kazon and its mother. The Kazon attacked the U.S.S. Voyager when it came for the child and were able to board and take over the vessel. During the short period when the Voyager crew was marooned on a planet, Seska learned the child was not Chakotay's but Culluh's, infuriating both herself and Chakotay.

Seska was killed when the Voyager crew successfully retook the ship from the Kazon. Her child was taken by Culluh.

Many months after her death, a holodeck program she had altered to kill Commander Tuvok was discovered in the ship's memory and nearly accomplished its purpose before it was successfully deactivated.