A Gamma Quadrant species torn by civil war, whose rebels created a perfect replicant of Miles O'Brien in an assassination plot.
The Paradans are a humanoid people of the Gamma Quadrant whose home system was split by a long civil war between the government and rebel forces. They are skilled at making replicants, artificial copies of living people so detailed that the copies themselves believe they are real.
In the episode Whispers, Miles O'Brien returned to Deep Space 9 to find everyone treating him with suspicion. The story was told from his point of view, and only at the end was it revealed that he was a replicant built by Paradan rebels to sabotage peace talks with their government. The real O'Brien had been held captive, and the replicant was fatally wounded before he could carry out his programming.