The Governor of Peliar Zel in The Host, who calls in the Trill ambassador Odan to mediate between her planet's two moons and accepts Riker as his temporary host.
Leka Trion is the head of government of Peliar Zel, a planet whose two inhabited moons, Alpha and Beta, have a long history of quarrels. She appears in the fourth-season episode The Host, set in 2367.
The latest dispute, over an energy source on Alpha that is damaging Beta's environment, threatens to turn into war. Trion has asked for Ambassador Odan, whose family has mediated between the moons before, and the Enterprise is bringing him.
When Odan's shuttle is attacked and his host body dies, the symbiont is placed in Riker until a new Trill host arrives. Trion is taken aback, but after hearing Odan speak through Riker she agrees to continue and persuades the delegates of both moons to accept him.