Warning: contains spoilers forStar Trek: Defiant#20!
Star Trekhas finally shed light on Chief O’Brien’s dark backstory, and it is far more gruesome than fans imagined. O’Brien, who went to teach at Starfleet Academy at the end ofDeep Space Nine, now finds himself face to face with Romulans in the Delta Quadrant. InStar Trek: Defiant#20,O’Brien’s new dilemma stirs up memories of his most brutal and traumatic moment.
Chief O’Brien entered IDW’s revitialized line ofStar Trekcomics in this year’sAnnual.

Star Trek: Defiant#20 is written by Christopher Cantwell and drawn by Angel Unzueta. The issue opens with O’Brien recounting the Battle of Setlik III to Doctor Bashir. O’Brien, who was serving on theRoutledgeat the time, was fighting a small division of Cardassian soldiers.O’Brien eventually came face to facewith the leader of the army. The Cardassian taunts O’Brien, who then fires his phaser. O’Brien thought the phaser was set to stun, but instead the beam went straight through the head of the Cardassian, killing him instantly.
Chief O’Brien’sStar TrekArc Has Been Long–and Brutal
Chief O’Brien Has Faced a Lifetime of Trauma
Chief O’Brien, played by Colm Meaney, appeared in the first six seasons ofStar Trek: The Next Generationas a reoccuring guest-star, before beaming over toDeep Space Nine, where he served for seven seasons.
Chief O’Brien began as a one-off character appearing in the pilot episode ofStar Trek: The Next Generation, and would go on to become a franchise favorite. DuringThe Next Generation’sfourth season, fans got their first glimpse into O’Brien’s backstory. During the episode, titled ‘The Wounded,”O’Brien revealed a traumatic event from his previous assignment, the same incident depicted in the opening pages ofStar Trek: Defiant#20.As a result of the encounter, O’Brien developed a deep disdain for Cardassians, which would take him many years to process and begin to work through.

Unfortunately, O’Brien would often suffer after he transferred toDeep Space Nine, where he was Chief of Operations. In the fourth season episode “Hard Time,” O’Brien “served” 20 years in a virtual prison. It was only an illusion, but the experience was real for O’Brien, and the trauma of it haunted him deeply. This was only one of many traumatic incidents Chief O’Brien was forced to endure.O’Brien being traumatized occurred so frequently throughout theStar Trekfranchise that it became a meme among fans.
Setlik III Would Come to Define Chief O’Brien’s Starfleet Career
Setlik III Was Far Gorier ThanStar TrekFans Could Have Imagined
O’Brien always told himself killing the Cardassian commander was self-defense, but the doubts continue to plague him, years after the incident and his return to Starfleet Academy.
Andwhile O’Brien suffered arguably greater traumas after Setlik III, it would remain the one that defined him the most.O’Brien was still young when he took part in the fighting at Setlik III, and killing the Cardassian was the first time he was forced to take a life. In “The Wounded," O’Brien said he never even hurt a fly before Setlik III, but being forced to kill changed him deeply.O’Brien always told himselfkilling the Cardassian commander was self-defense, but the doubts continue to plague him, years after the incident and his return to Starfleet Academy.

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Despite being the trauma that defined Chief O’Brien’s Starfleet career, it has never been seen on-screen, leaving it to the imaginations ofStar Trekfans—until now. In “The Wounded,” O’Brien did not mince words when talking about Setlik III, and as seen inStar Trek: Defiant#20,it was far more brutal and gory than he let on.Cantwell and Unzueta did not pull any punches in depicting the incident, and it is clear to see why it traumatized Chief O’Brien. The incident on Setlik III set a precedent for Chief O’Brien, one that continues to this day.