Protector Colyus was a holographic Yaderan male created by Rurigan, a Yaderan who left his homeworld after the Dominion captured his world and changed the planet's society. The village created by Rurigan on Yadera II in 2340 was a recreation of all that he had lost.
Colyus, not knowing that he was one of the holograms, served as protector of a village for ten years and was investigating the disappearances of twenty-two villagers, including his nephew, in 2370. When Jadzia Dax and Odo landed on the planet, Colyus arrested them thinking that they were responsible for the missing people. Odo and Dax eventually helped Colyus solve the mystery. Dax and Odo discovered that all the villagers, except for Rurigan, were holographic projections and that a faulty projector was responsible for the disappearances.
At first, Colyus did not believe them, but after they convinced him, he persuaded his people that if they wished to continue to exist they must allow Dax and Odo to take them off-line temporarily and repair the projector before it experienced a complete failure. They agreed and Colyus and the rest of the village were restored. (DS9: "Shadowplay")