Leonard de Vries

De Vries was the leader of the religion of the Cailleach.

Biography
De Vries and Martha were in the group, but after the Cessair of Diplos wanted the whole area around her dead, she ordered her Ogri to kill him. The Fourth Doctor and Amelia Rumford found his body, at that time when K9 traced an Ogri, ready to kill. (TV: The Stones of Blood)