Agachak was the Grolim Hierarch of Cthol Murgos, specifically of Rak Urga. He was a cadaverous man who enjoyed games of power and manipulation. He wore a blood-red hooded robe and had a long beard, sunken eyes, and shaggy gray brows. He had a hollow voice. He brought King Nathel of the Thulls with him to Korim. On the way Agachak was killed by Zandramas in her form as a dragon.