Ruen was a trained monk and rogue who lived in the Mistshore section of Waterdeep harbor. He was a companion of the young wizard Icelin Tearn and the butcher Sull. He was an expert in weaponless combat and held the distinction of being the only person to "escape" from Waterdeep dungeon.
As a child, Ruen enjoyed playing in the woods. One day, he waded into a pool and was touched by spellplague that was lingering in the water. His spellscar gave him the ability to know the date of a person's death by touching them. This ability upset the residents of his village and he left to study at a monastery.
Ruen became a successful rogue in Waterdeep but was captured by the Watch and imprisoned. The Watch made a deal to allow him to escape if he would become an informant in Mistshore. While in Mistshore, Icelin approached Ruen and hired him to protect her from the gold elf Cerest Elenithil, who was trying to capture her. Ruen successfully hid Icelin for a while and helped her kill Cerest when he finally caught up to her. He left Waterdeep with Icelin and Sull on a journey to attempt to find a cure for Icelin's spellscar.
Ruen had a ring that enhanced the effects of magic.
Ruen was tall and extremely thin. His spellscared eyes were red. He wore an old floppy hat.