Okoth was a Unknown that lived a long time ago, somewhere around the Cathedral of Grey Grace. Together with Trakan Sparrowtuft and Galfast Hamhead, he participated in the events that led to the civil war between three Halfling factions, in the war itself, and in its aftermath. During the shared vision that occurred during Take Me to Church, Lanliss Ashscribe was the one seeing through Okoth's eyes.
Okoth was a Cleric of the Radiance, or the Sun-in-Splendour, the deity of the Halflings of the White Banner, aka the Halflings of the Ivory.
Okoth was the nephew of Saint Odwulf Goldbreeze, who was also seen in the shared vision. He betrayed his uncle, and helped kill him, though came to regret it.