Gemini Aspros (双子座のアスプロス, Jemini no Asupurosu?) is Gemini Defteros' late twin older brother. Once a virtuous Saint, Aspros was executed for plotting against the Sanctuary and wanting to steal Athena's Cloth to rule over Sanctuary. When the brothers reminisce about their past, it is revealed that rumor in Sanctuary had Aspros as the virtual successor of the Pope, however, the latter chose another prospect he considered the fittest. Enraged for having failed in attaining his goal of becoming Pope of the Sanctuary, Aspros violates the sanctity of Star Hill, a place reserved only to the Popes, and steals secrets kept there for ages. It is also revealed that the year his execution took place, Aspros manipulated Defteros with the forbidden technique that he learned in Star Hill, the Demon Emperor's Delusional Fist (幻朧魔皇拳, Genrōmaōken?), in order to assassinate the Pope of Sanctuary, taking advantage of the fact that Defteros existence was almost totally unknown. As Defteros trespassed the Chambers of the Pope to fulfill his mission, he was stopped by his brother, who pretended to protect the Pope and to be ready to kill his brother in punishment for treason. As the Pope turned his back to avoid the scene, Aspros prepared to kill him, only to be stopped by Virgo Asmita. After Defteros was freed by Asmita from the effects of the Delusional Fist, Aspros received his brother's lethal attack. The Pope reveals that his seat was destined to be Aspros' had he not deviated from the path of virtue. Humiliated by his defeat at the hands of whom he considered a shadow, Aspros applies his Delusional Fist on himself, to assure he would achieve his goal even if having to return from beyond the grave. His body was taken by Defteros to Kanon Island. After being resurrected by Hades, he appears before his brother immediately after the latter saves Libra Dohko from Bennu Kagaho, and engages him in battle. Revealed by Hades to be also the guardian of the Fourth Demon Temple: Mars (第4魔宮火星, Dai yon Makyū Marusu?). As a servant of Hades, he was granted the Gemini Surplice, a dark reflection of the prideful Gold Cloth he once wore. In the past, 16 years before the events depicted in Lost Canvas, Aspros shared with Defteros the dire trials required to become a Saint. Aspros was very protective of his younger brother, who was considered a wasted life born under an unfortunate star. Years later, bearing a grudge against his brother for his execution, Aspros tries unsuccessfully to kill his twin during their encounter in the Mars Temple, with their signature and most destructive technique: Galaxian Explosion (ギャラクシアンエクスプロージョン, Gyarakushian Ekusupurōjon?), a massive burst of Cosmo that easily vaporizes opponents, said to be capable of smashing stars. Aspros overpowers his brother with ease, and reveals his gentle nature of the past was but a facade, as his goal of domination required him to become purely evil. Determined to end the battle, Aspros clashes with Defteros in a final effort. Consuming his brother's Galaxian Explosion with his own, Aspros believes himself the victor, only to realize that during the clash, his brother sacrificed his life in front of him, negating the effect of the Delusional Fist, and thus making him return to his old, good-natured self, and is accepted by the Gemini Gold Cloth. Aspros then turns on Hades revealing his intentions, only to be stopped by Mephistopheles Yōma, who dissolves his body into quantum particles. Later on, Aspros show up again for a revenge against Yõma, he used his Another Dimension to protect himself against Yõma attack.