Kellus Therran is the name of an ancient powerful wizard, one of the 5 who founded the white magic school of Thyckletray.
Kellus is not widely regarded or known in the current magical study. The only known repository of his studies and books is at his tower in Thyckletray. It is said that he studied strange magical myths and legends, especially magical creatures.
Aeli, a current PC in the Vale campaign, is a descendant of Kellus.