Guus was an Ogre Mage under the command of Ole during the era of King's Quest ZZT 2. When Alexander challenged Ole, Guus was commanded to kill Alexander with his magic. Alexander fought him in battle, and finally defeated him. In his last breath Guus cast a destructive fireball spell to try to destroy Alexander, but he had escaped from the Ogre Base along with Thorm during the confusion.
The spell was wrongly cast and caused the base to explode taking out all the other ogres with it.
Guus is able to hit with his mace, and cast magic missile and burning hands.