Cadwell the Betrayer

Cadwell the Betrayer is the person that the Soul-Shriven Sir Cadwell of Codswallop was in life—a hero who helped Khunzar-ri and his kra'jun seal the dragons away in the Halls of Colossus only to betray him in an attempt to take the power sealed away in the Plane of Jode. He died during his last stand in the Shadow Dance Temple during the Merethic Era, with his remains scattered across the land and his name wiped from all records.

Source: uesp.net.