Tasha Yar died in the first season of Star Trek history. She was an integral part of the Enterprise-D's senior staff over the first half of Star Trek: The Next Generation season 1, forming close bonds with Lieutenant Commander Data and Lieutenant Geordi La Forge in particular.
Tasha Yar was shockingly killed off in the Star Trek: The Next Generation episode "Skin of Evil." She was the first regular Star Trek cast member to not only die but to stay dead. Tasha's legacy would endure over Star Trek: The Next Generation's seven-year run, however, with Crosby reprising the role and expanding it in some surprisingly innovative ways. Crosby has also hinted at Tasha Yar's return in Star Trek: Picard season 3 in some way as well.
Why Tasha Yar Was Killed Off In TNG Season 1
Despite its impressive viewing numbers, Star Trek: The Next Generation season 1 was a well-documented mess behind the scenes. Franchise creator Gene Roddenberry was not a well man by that point, quietly suffering a series of mini-strokes while the production of Star Trek: The Next Generation went off the rails. Beyond his ill health, Roddenberry was simply not accustomed to the more complicated process of making television in the 1980s; the show had a revolving door of a writers' room and no official showrunner until season 2.
The biggest casualty of Star Trek: The Next Generation's production chaos was the quality of the show's writing. Season 1 saw some of the worst episodes of Star Trek: The Next Generation like "Code Of Honor" and "Angel One," which were not only poorly plotted but actually undermined the core ethos of Star Trek with their racism and sexism. The ensemble cast was often relegated to the sidelines in favor of Commander Riker or, bafflingly, Wesley Crusher. By mid-season, Denise Crosby had enough of her character's stagnant development and requested to leave the show. Roddenberry obliged her by abruptly killing off Tasha Yar in "Skin Of Evil," another lousy episode that killed off a main character for seemingly no reason.
How Tasha Yar Returned In “Yesterday’s Enterprise”
Much had changed by Star Trek: The Next Generation season 3. The ailing Gene Roddenberry was no longer in creative control of the show, having handed the reins to producers Rick Berman and Michael Piller, who would oversee Star Trek's golden age over the 1990s. Star Trek: The Next Generation took a quantum leap forward in quality when Piller became the show's head writer in season 3. Crosby noted the show's improvement and still had much affection for the cast, so she indicated she'd be willing to return as a guest star.
That came to fruition in the classic Star Trek: The Next Generation episode "Yesterday's Enterprise." When a temporal anomaly prevents the Enterprise-C — the predecessor of Picard's Enterprise — from carrying out its final, crucial mission, a dark new timeline is created. Tasha Yar is alive and well on the Enterprise-D, but the Federation is mired in a hopeless war against the Klingons that has claimed billions of lives. Tasha eventually chooses to return to the past with the hobbled Enterprise-C to ensure their mission is a success, restoring the timeline and seemingly ending her life with real purpose. But that wouldn't be the end of Tasha's story.
Tasha Yar’s Daughter Sela Explained
Once the Enterprise-C returned to its own time, it was soundly defeated by a Romulan ship that was attacking a Klingon outpost. There were survivors, however, including Tasha Yar, who was sent to Romulus where she was to be questioned and executed. She caught the eye of a powerful Romulan politician and her life was spared, as she became his consort. Tasha would give birth to a half-Romulan child, Sela. She attempted to escape Romulus with Sela, but the young child alerted security, and Tasha was executed.
Also played by actress Denise Crosby, Sela would grow up to be an influential Romulan officer who would confront Picard and the Enterprise in the Star Trek: The Next Generation two-parters "Redemption" and "Unification," the latter of which saw her face off with Leonard Nimoy's Spock as well. It's unknown what happened to Sela after "Unification," or if she survived the Romulan supernova.