By magic he turned away those who sought treasure and killed those who foiled his clouding of their minds, until Macros the Black found him and learn his magic so that it could not be lost. Afraid that he came for his riches, Rhuagh battled for days but was unable to defeat him; Rhuagh then taught him as much as he could for three years and became his first human friend; Macros also taught Rhuagh about healing the wounds of the heart and mind, and how to respect all life.
Ruagh then sickened of the killing and vowed to take no more lives. Before leaving, Macros left a last gift for him, a magic rod to be used upon the dragon's death, so that no bones should be left for the scavengers.
After years he became blind and could see only by magic. He was discovered by kobolds who because of their religious nature, they worshipped the dragon as a god bringing him fish caught in the deep lake and treasure gleaned from deeper halls.
When Tomas was lost in Mac Mordain Cadal, he found himself in an abandoned palace; following a band of moredhel and goblins, he was led to the throne room where Ruagh was sitting. Rhuagh turned the band away but let Tomas stay and fed him with smoked fish brought by the kobolds. Not long after, Tomas was found by Dolgan.
After passing his first shock, Rhuagh explained to Dolgan his intentions and about his long life: Rhuagh only wished that they should stand as witnesses for his deathwatch since he knew that his time was near, and there were no dragons with him to watch. He also offered them two boxes as gifts for them to take.
As asked, Dolgan touched Rhuagh with Macros' rod. For some moments the dragon started to glow, his vision was restored and his dull scales glowed again. As the two guests watched him rise and open his wings, the dragon vanished.
After the Riftwar, the kobolds after their leader Feydhir took a holy quest to find the dragon Rhuagh and caused trouble to the dwarves. Their exploits awoke a Brak Nurr which collapsed the main passage and killed 30 dwarves. There was a reward for anyone who would kill it.