Azal

Azal was the last living Dæmon. Thousands of years ago, he placed himself in suspended animation in his spacecraft under Devil's Hump until the time came to judge if the Dæmons' experiment with humanity were a success or a failure.

In the late 20th Century, the Master awoke Azal, planning to have the Dæmon pass on his power to him. Azal instead offered his power to the Doctor, who refused. When Azal decided to kill him, Jo Grant offered to take his place. Azal, unable to comprehend this seemingly irrational act of self-sacrifice, self-destructed. (DW: The Dæmons)