Zygon is the main antagonist of Starchaser: The Legend of Orin.
In a distant planet named Trinia, human slaves have lived underground for many years and mine for crystals for a "god" named Zygon and his robot minions. During another day of mining, Orin, the hero of the film, finds a jeweled sword embedded in the rocks. One of the slaves recognizes the sword and is killed by one of the robots in order to keep the sword a secret. When Orin later takes the sword into his hands, it ascends into the air and buries itself in the cavern's floor. A projection of an old man appears from the blade, saying that above the caverns is a "magnificent universe" that the people may find. The blade then disappears, leaving only the hiltOrin and Elan, one of the miners, embark to discover the said universe and find the blade to the sword. They eventually run from the mines to a military base, where they meet Zygon. Zygon kills Elan, but Orin manages to escape. When Zygon's robots fire on him, they strike a crystal deposit, and in the resultant explosion Orin is hidden from Zygon and presumed dead. Thereafter, Orin digs a tunnel to the surface of Trinia, where he is later captured by Man-Droids, a group of decaying half-organic, half-robotic beings who intend to tear him apart and use his body parts to replace their own. Unexpectedly, his sword's hilt produces what is apparently an invisible blade, killing two of the Man-Droids and helping Orin escape. Orin subsequently runs into a human smuggler named Dagg Dibrimi, who takes Orin along on his journey to smuggle crystals. Eventually, Dagg seizes a load of crystals from a hovering freighter, but is driven away by Zygon and his robotic guards. During the fight, Dagg seizes a Fembot and uses it as a shield from laser blasts. Subsequently re-programmed by Dagg, this Fembot, named Silica, becomes attached to him.
Dagg flies the Starchaser to a city called Toga-Togo on the planet Bordogon, where he abandons Orin and gives Silica to a slave auctioneer. Orin then wanders through the city, trying to find a clue that will lead him to the location of the hilt's blade. Just then, Orin meets a fortune-teller, who tells him to visit a place called Novaluna. Later, Orin sees Silica offered for sale, whereupon he offers high prices to buy her. When the auctioneer finds that Orin has no knowledge of local currency, he takes Orin's freedom in addition to Silica's; but Dagg, moved by his own conscience, frees them. Later, Dagg and Orin visit the home of two desert-dwelling merchants, to whom Dagg sells the stolen crystals. Because Zygon has placed a price on Orin's head, the merchants offer to buy Orin as well, but Dagg refuses. In response, the merchants place a time bomb in Dagg's payment. Orin is forewarned by a mysterious "Starfly", whereupon Dagg and Arthur throw the money and bomb into their enemies' camp. Thereafter Dagg agrees to take Orin to Novaluna; but they are shot down by Zygon's robotic soldiers. Dagg is captured, the ship is inactive, and Orin is thrown clear of the ship and is rescued by Aviana, the daughter of Bordogon's Governor.
Upon having woken and met Aviana, Orin tells her of his whereabouts, whereupon Aviana's computer reveals that the hilt has historically been used by a group of legendary guardians called the Ka-Khan to vanquish threats to humanity. Among these threats was a tyrant called Nexus, after whose defeat the hilt vanished until Orin's discovery of it. Aviana thereafter takes Orin to Trinia, where he again faces Zygon. Orin attempts to kill Zygon for Elan's death and exposes him as a robot. Zygon then reveals that he is Nexus, seeking again to rule over humanity with his army of robots. Zygon takes Orin's hilt and begins to co-ordinate the attack. Orin and Aviana are imprisoned in the cell block wherein Dagg is also captive. As Orin and Aviana confess their feelings toward one another, Aviana is taken aboard Zygon's flagship as a hostage. Orin is again approached by the Starfly, who brings him the hilt, which he uses to free himself and Dagg. They enter Zygon's flagship and take control of it, using it (again aided by the Starfly) to destroy the enemy fleet. They are rejoined by Silica, who has restored the Starchaser.
Orin and his friends penetrate Zygon's base, but are attacked by his remaining troops. While Dagg and Silica stay behind to fight off their pursuers, Orin enters his original cavern home and begins to denounce Zygon, but is interrupted by Zygon himself. They fight, resulting in Orin dangling over a chasm, while Zygon gloats over him. As Orin hangs over the chasm, three Starflies appear and merge into one; but instead of giving him the hilt at his request, it states that he has no need of the hilt, adding that "there never was a blade". Orin therefore realizes that the power to create a cutting force came from himself. At this, he pulls himself up, generates such a force, and uses it to kill Zygon. Orin's people rise in revolt and win freedom.