Radregh was an Alsheen time-traveller present during the foundation of the Institute of Time. Radregh asked the Eighth Doctor if the Institute would be still standing at the end of the universe.
The Doctor travelled ahead to the end of the universe and found that Radregh and the other members of the Institute had committed suicide. When he returned back to his original time, he refused to tell his friends what he had found. (PROSE: The End)