Leonard de Vries
From Tardis Wiki, the free Doctor Who reference
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 Doctor and Amelia Rumford found his body, at that time when K-9 traced a Ogri, ready to kill. (DW: The Stones of Blood)