Walter Simeon
Dr Walter Simeon was a man associated with the Great Intelligence. He found it as a young boy, and unwittingly began pouring his darkest thoughts into the Intelligence. Believing its orders to be its own rather than a reflection of himself, Simeon began to go about building an army of ice for himself to be in power.
To this end he established the Great Intelligence Institute and sought to bring the Ice Governess to the Intelligence, which brought him up against the Doctor. When he confronted him at the Institute, the Doctor showed him how the Intelligence was nothing more than a reflection of Simeon himself rather than a separate entity. Undaunted by this revelation, Simeon sought to get the remains of the Governess, but tricked him into being bitten by a memory worm. The memories of his adult life were erased, but the Intelligence had by this time gained enough independence to survive and fill in the void left and take over Simeon's body. After a brief scuttle with the Doctor, whatever was left of Simeon died when the Intelligence was defeated and relinquished control of his body. (TV: The Snowmen)
