Gemini Saga (双子座のサガ Jemini no Saga?) served as the main antagonist for the Sanctuary arc. Being an excellent strategist, Saga managed to put himself in control of the sanctuary (though unfairly) for many years. Before the final showdown between himself and Pegasus Seiya, Saga was portrayed as a mysterious being with his facial features hidden from view. Saga is often described by other characters as someone with the kindness of an angel but with the darkness of a demon. This ambivalence ended up creating a split personality: a good Saga that was extremely loyal to Athena and an evil one that keep the control of the body most of the time and killed the previous Pope to steal his place.
Sometimes it is hinted that the creation of his "bad" personality had the influence of some external force, although nothing was clearly stated. When it takes the control of Saga's body, his hair turn from blond to jet-black (the color schemes were altered for the anime, in which Saga's normally blue hair turned light grey). Saga's two "sides", can also communicate between them : in a dialogue the good Saga reproaches his evil "side" to have forced him to hurt Athena.
As one of the twelve Gold Saints, Saga was greatly skilled in all aspects of combat. He possesses light-speed attacks and strong mental-psychic powers, which allow him to create vivid illusions and distort time and space(Another Dimension). He is able to do this at great distances after mentally locating the opponents exact position. As an example of his great power, Saga was able to deprive Pegasus Seiya of his five senses using Cosmo energy blasts from his fists. In the anime, he is also able to deflect a triple attack from three Bronze Saints who acquired the 7th sense (although it's hinted that they hadn't mastered the 7th sense, so they're weaker than a Gold Saint), with minimal effort.
Many consider Saga to be one of the most powerful of all Gold Saints, including Virgo Shaka.
Another Dimension (アナザーディメンション Anazā Dimenshon?) Allows him to bend space and time itself provoking a rift or a passageway to a different dimension,intending to push and trap his opponents inside to wander forever after he has done this.The technique not only sends physical bodies to a different dimension but also intangible beings such as souls and spirits.An added fact about this particular move is that Saga can launch this at great distances,coupled with a very vivid illusion of himself wearing his armor,Saga thwarts the opponent into believing that he is in the given location performing the move,when in reality he might be miles away from the actual fighting ground.
Specter Emperor Fist (幻朧魔皇拳 Genrōmaōken?)This move directly strikes the opponents brain, the weak version can paralyse the opponent's nervous system for a few minutes, rendering him immobile and ultimately open to any attack. The more powerful version allows Saga to strike into the mind of his opponents allowing him to "brainwash" the opponent into doing his bidding and even make them go against their most precious assets. The effects of the power will only wear off if the victim complies with the brainwashed mission that Saga gave him when applying this move,in other words, if the person was sent to kill someone, that person will go back to his original self once he had committed the action of killing.
His most powerful attack is Galaxian Explosion (ギャラクシアンエクスプロージョン gyarakushian ekusupurōjon?). One of, if not the, most destructive moves in the entire Saint Seiya series, with the Athena Exclamation as the only exception. When used at maximum power, this move is said to be as powerful as the explosion of a star system or a galaxy, which is seen in the background whenever Saga uses this technique, and hence its name. Its blast can destroy intangible beings such as souls. In Saint Seiya Episode G this technique is explained indirectly stating that it resembles Leo Aiolias' Photon Burst, but actually does not leave the quasi-fatal after effects of Aiolia's photon burst or at least he seems to actually have mastered this move to a point were it does not have does after effects on him, thus leaving him able to do it once and once again.
Light Speed Punch (光速拳 kon cho ken?) He can generate multiple beams only by lifting his arm.