The Magistrate was the leader of the Olesian people.
His predecessors had put their Penal colony on the island with the Stargate so that the Wraith could feed on the prisoners, and not the Olesian population. After meeting Lt. Colonel John Sheppard's team, the Magistrate met with a Wraith for a meal, where the Wraith told him that he called other Wraith so that they may also feast on the planet's people. After this, the Magistrate ordered several people to be arrested so as to feed the approaching Wraith. After the prisoners escaped through the Stargate, the three Wraith cruisers headed for the mainland as the Magistrate watched on in horror. (SGA: "Condemned")
A week and a half later, after encountering a seemingly similar situation on M32-3R1, Teyla Emmagan told Sheppard of how Weir suspected the Magistrate of having a deal with the Wraith. While the two suspected the people of M32-3R1 had a similar deal initially, they eventually came to realize that the High King and the planet's "gods" were in fact the Wraith. After realizing that the Games of Life were just a way to stock the High King's feeding pen, Sheppard commented on the fact that the Magistrate and the Olesians at least had the decency to accuse someone of a crime before feeding them to the Wraith. (SGA: "Death Game")