Gigas (ギガース, Gigāsu) is chief of staff for the Pope. He is a short, aged man with a strange jewel replacing his left eye. He appears only in the anime adaptation and thus is a non-canonical character in the manga.
Gigas is the personal adviser to the Pope Arles who commands and directs the missions of the Saints of Athena's Sanctuary. Gigas sent Docrates to Japan in order to recover the Gold Cloth of Sagittarius. Shortly after, Docrates reports to have recovered all the armor pieces except for the mask, and because of the delay in recoveringt the mask, Gigas instructed his subordinate, Phaeton, to tell Docrates not dare to return unless he succeeds in retrieving the missing part.
Gigas informs Pope Ares about Docrates' situation in Japan, and the Pope orders Gigas to tell Docrates that Pegasus Seiya must die, and if successful, he will be rewarded as he deserves. Later Gigas informs Pope Ares about Docrates' death and complete failure both in the attempt to get the mask of the Golden Cloth of Sagittarius and kill Seiya. Pope Ares reminds Gigas that he'd pay his failure with his own life. Gigas begs for mercy and claims he has come up with a plan to eliminate the Bronze Saints and recover the mask. The Pope decides to give him another chance since the majority of the Gold Cloth of Sagittarius has been retrieved.
Gigas seeks advice from Ophiuchus Shaina and she requests him to be sent to Japan, but he thinks it over and decides to keep her as an ace under his sleeve. Shaina then suggests Gigas he uses Geist and the Caraib Ghost Saints, who live in exile on Castle Island after getting expelled from the Sanctuary by the previous Pope upon their involvement in criminal acts. They send a carrier pigeon with a message to Castle Island to tell Geist about the mission.
Gigas promises Shaina that if Geist fulfills her mission, she and her associates will be granted a pardon and be allowed to return from their exile. Shorly after, Gigas learns about the defeat and death of Geist and the Caraib Ghost Saints. When he breaks the bad news to Pope Ares, the latter bursts into rage and recriminates Gigas for both not keeping his word and not doing his duty.
Pope Ares decided to give Gigas yet one more chance to redeem himself by returning the mask of the Gold Cloth of Sagittarius to the Sanctuary. Gigas leaves the Chamber of Pope Ares thanking him for his clemency. After that, he tells his subordinate Phaeton that he wants the head of Seiya and the other Bronze Saints, and for that purpose, he thinks of using Crystal Saint, Cygnus Hyōga's master.
As Crystal Saint arrives in the Sanctuary he expresses his contempt for Gigas for having betrayed his sacred duties, and an argument quickly ensues. As Crystal overpowers Phaeton, Gigas alerts the Sanctuary guards and directs them to detain Crystal, but they are no match for the Silver Saint. Then he turns his anger against Gigas, and as he is about to finish him off, the Pope shows up and commands him to stop. Crystal urges the Pope to bring the Santuary to the right path, but the Pope responds that he has no right to question his actions. Then he proceeds to seize Crystal´s mind using his secret technique, Genrō Maō Ken (Satanic Imperial Fist), demands his undying loyalty, and orders him to kill the Bronze Saints. The whole scene is witnessed by Marin, Seiya's master.
Crystal then goes to Siberia to kill Hyoga. Gigas also gives the order to imprison the Siberian villagers living with Crystal to build a pyramid of ice to honor the Pope.
After some days, Phaeton informs Gigas that the construction of the pyramid proceeds at a good pace, but doesn't know anything about Crystal. Gigas says that they should accelerate the pace to finish as soon as possible to jave a representation of the power of the Pope. Gigas believes the Pope will reward him when the pyramid is finished.
Later Phaeton informed Gygas that Crystal has failed and is dead, and that the pyramid of ice was destroyed. Gigas prefers to not inform the Pope in fear that if he discovers it he will cut his neck. Gigas says that since Pegasus Seiya and Cygnus Hyoga are currently in Siberia they will use the opportunity to attack the Kido Estate.
Gigas takes with him the Ennetsu Saint (Saint of the Flame) and several guards from the Sanctuary to Japan. They attack the Kido Estate to make Saori come out of hiding and find the gold mask. As the estate is empty, Gigas orders the Ennetsu Saint to destroy it in hopes that this will make them reveal their position.
Tatsumi goes to the mansion to see in person what happened and Gigas knocks him down with his cane. Gigas traps Tatsumaki and tortures him to reveal where the mask of the Gold Cloth of Sagittarius was hidden. After learning the location, Gigas and the Ennetsu Saint go to Saori's hideout, with Gigas telling the Ennetsu Saint that the Pope will reward them for retrieving the mask.
In the hideout, Gigas and his men attempt to invade the house, but Andromeda Shun protects it, entering in a fight against the Ennetsu Saint while Gigas attempts to enter the house. Shun has trouble against the Ennetsu Saint, with his defeat being imminent. Gigas gets inside the house and finds Saori with the golden mask, telling her that her guardian has lost and that she should give the mask. Saori accepts in exchange for the release of Shun from the flames. Just at the moment in which Saori would give the mask to Gigas, they feel a strange Cosmo outside. Phoenix Ikki arises from the flames and saves Shun.
Gigas is glad to see Ikki and tells him they are about to recover the mask of the Gold Cloth of Sagittarius. Gigas says that the Pope will be happy to see him, and tells Ikki that he, too, will be happy to make the Pope pay for everything he did. Ikki then knocks down Gigas, who tells Ikki he will regret this betrayal while collapsing on the floor.
When Gigas rises, he saw that Ikki had killed the Ennetsu Saint. Gigas and the Sanctuary soldiers who accompanied him run away. Since then Gigas disappeared and is not seen again, with his subordinate Phaeton taking his place.