Gaal

Gaal is a Human cleric/mage and a high priest of his' beholder cult God, the Unseeing Eye.

You will first find Gaal preaching to some Athkatlan citizens in the Athkatla Temple district and trying to get them to join his cult. After you will be asked to investigate the cult.

You will then find him in his cult area in the Temple district sewers in which case he will ask you to retrieve one half of a powerful artifact. After killing his God it is possible to return to where you first met Gaal in the cult area and kill him along with some other priests.