Omega's Champion

Omega's Champion was an entity that existed within Omega's anti-matter universe, being an embodiment of the "dark side" of Omega's own mind and therefore, in a way, an extension of Omega himself. The entity served as his proxy to battle the Third Doctor. (TV: The Three Doctors, PROSE: The Three Doctors)

Biography
Like the Gell guards, and the rest of the antimatter universe, the Champion was a creation of Omega, sustained by his will. However, Omega described the Champion as "the dark side of [his] mind", suggesting a deeper identification between them. When the Second and Third Doctors, in the room containing the black hole's singularity, challenged Omega to a battle of wills, Omega accepted. The Third Doctor collapsed, and found his mind trapped in a black void, where Omega ordered the Champion to destroy him; he responded with Venusian aikido, but was soon overpowered. Meanwhile, the Second Doctor pointed out that killing him would lose Omega his chance at freedom; Omega ceased the attack, and the Third Doctor woke up, and thanked Omega for "a most interesting demonstration". (TV: The Three Doctors)

According to another account, Omega physically rearranged the room so that the Third Doctor suddenly found himself in a Roman-style colosseum under a purple sky, with Omega observing him from a viewing stand; the Second Doctor found himself beside Omega, paralysed. The Champion entered through an arena door, which then disappeared. The Third Doctor initially thought "Demon, Ghoul, Monster", but suddenly found its "hideous face" reminiscent of Omega, and realised that the Champion, in a sense, "was Omega": since Omega's thoughts and feelings were real in the antimatter universe, "this ghastly creature was an incarnation of all the rage and hatred that Omega felt towards the Doctor." (PROSE: The Three Doctors)

In the Infinity Doctor's reality, when Omega unleashed the Dark Design across Gallifrey, he physically transformed into a vast hunched creature like a bull or warthog, with horns and a large beard. (PROSE: The Infinity Doctors)

Appearance
The Champion was a hunched, hairless biped with pallid flesh. It had an elongated, sloping head with a furrowed, lined face, a flat snout, and pointed, bat-like ears. Its body was covered in reflective crystalline or metallic plates, evocative of Omega's own armour. The Champion appeared variously yellow-green and purple throughout the battle. (TV: The Three Doctors)

According to another account, the Champion was more than eight feet tall, and made of a substance like smooth black granite. It had powerful limbs knotted with muscle, long talons, an ape-like head, and a fanged, slavering mouth, with breath like sulfur. (PROSE: The Three Doctors)

Behind the scenes

 * The creature was described in the script as "a ferocious alien giant". (DWM 260, DWM 409)
 * The Champion was portrayed by an uncredited Alan Chuntz (DWM 260), a stuntman who played numerous non-speaking characters from season 6 through season 19. His one credited appearance was as the chauffeur in The Seeds of Doom.
 * The name "Omega's Champion" does not appear in the serial, but was used in behind-the-scenes documentation. (DWM 260)