Zarm is one of the three beholders appearing in The Sword of Frost, the eighth part of Heroes Chronicles. The other two are Neez and Kilkik.
When Tarnum was leading the armies of Nighon to stop Gelu from claiming the Sword of Frost and potentially destroying the world, he was attacked by a medusa that wanted to slay him and take control of his army. The three beholders killed the medusa and saved him, hoping he would reward them well, and Tarnum made them his advisors and guards. They would lead the army, second only to him. While Tarnum was glad for their protection, he also knew not to trust them.
Neez learned that the ten hatchlings of the treacherous medusa were plotting against them. Deciding to strike first, Tarnum and the three beholders ambushed the medusas while they were preparing a poison. While the medusas were slain, Zarm also lost his life in the struggle.