The Determinant

The Determinant was a realm created and controlled by from the planet of Siralos. It was made of pure psychic energy. The Master planned to use it to bend the universe to his will. To this end, he had captured seven of the Doctor's incarnations. He was defeated by the Graak, a creation of the Doctor, who completed the various challenges set up by the Master within Determinant. (GAME: Destiny of the Doctors)
Category:Locations visited by the First Doctor
Category:Locations visited by the Second Doctor
Category:Locations visited by the Third Doctor
Category:Locations visited by the Fourth Doctor
Category:Locations visited by the Fifth Doctor
Category:Locations visited by the Sixth Doctor
Category:Locations visited by the Seventh Doctor