Once the Tevinter Dragon of Beauty, Urthemiel was worshiped by musicians, artists, and poets in ancient times. The Feast of Urthemiel was the largest celebration of the year, an event that lasted a full twelve days. Plays and entire symphonies were written in his honor.
Shortly before the events of Dragon Age: Origins Urthemiel is awakened and transformed into the an archdemon in 9:30 Dragon by the darkspawn and is now a maddened husk of his former self, filled with nothing but a desire to destroy all life. This contrasted greatly with the commonly held-opinion that he was the fairest and most graceful of the Tevinter Old Gods.
In the events of the game the archdemon Urthemiel is leading the fifth blight against Ferelden.