Vorlon ambassador to Babylon 5. Arrived in 2257; remained there until his death in 2260.

Kosh took a certain interest in Captain Sheridan, teaching him about the Shadows and his own race, and saving Sheridan's life in 2259 by leaving his encounter suit to rescue him.

For providing Vorlon assistance to battle Shadow vessels in 2260, Kosh was killed by Morden and his Shadow accomplices, though a "piece" of him remained with Sheridan until 2261.