In the early days of the First Age, Karleg became the warlord of Azmar Island and founded of the Realm of Azmar.

He organized and led the Azmar Army and built Azmar Castle. He led the forces of Azmar in the Ogre Wars. He appointed the elf ranger Thaero as High Ranger of Azmar. He annexed Sheep Island into the Realm of Azmar. He was responsible for the discovery of Ogre Island and launched an invasion of it that resulted in the Battle of Ogre Island. In that battle, he was killed and eaten by a dragon called Zern.

After Karleg's death, his son Yarleg became the ruler of the Realm of Azmar, taking the title of Prince and calling himself Prince Yarl of Azmar.