Perseus Algol

 Perseus Algol (ペルセウス座のアルゴル, Peruseusu-za no Arugoru) is one of the Silver Saints sent to kill the Bronze Saints in the Sanctuary Arc.

Medusa Shield
He can utilize the Medusa Shield (based on the Greek mythological monster, Medusa), that can transform anyone who looks directly to it into stone. The shield's power works even if the target closes or covers their eyes, because it passes through blindfold and eyelid, and goes directly into the retina.

Sanctuary Arc
He was sent with two Silver Saints, Kerberos Dante and Auriga Capella, to kill the Bronze Saints. After Capella was killed by Phoenix Ikki's Phoenix Genma Ken, Ikki decided to leave, but gave the remaining Bronze Saints a bit of warning, stating the Algol is not the same as the other Silver Saints. Algol states that he could defeat all of them with the power of his Medusa Shield, and turns Shun into stone. Seiya, who took a fall earlier to protect Saori, was critically injured, and Shiryu stated that he must be given medical attention quickly. Algol now uses his shield on Cygnus Hyoga and Shiryu, turning the former Bronze Saint into stone.

However, Shiryu was not affected by this technique and told Algol that he used his shield to protect himself. He declared that he would defeat Algol to break the curse on his fellow Bronze Saints. Shiryu used his Rozan Shoryu Ha against Algol, but Algol evaded most of it, stating that he avoided it easily because Shiryu could not look at him and his technique was not aimed well. Thinking of the legend of how Perseus slayed Medusa, Shiryu decided to use his shield as a mirror, but Algol's movements were too fast, and he could not keep track on it. He must also use his shield to protect himself from Algol's attacks and the Medusa shield, keeping him from fighting back. Shiryu then decided rip a piece of his shirt off and use it as a blindfold, hoping that it would protect himself from the attack. But the Medusa Shield still worked despite the blindfold and turned the left half of his body into stone (hence he could not move or use his shield).

Knowing that Shiryu is now defenseless, Algol was about to use his shield on Shiryu. However, Shiryu hit his eyes with his fingers, not piercing them, but effectively blinding himself, so that he could no longer see the shield of Medusa. Although shocked by his action, Algol stated that he could defeat him without the shield of Medusa. Shiryu charged up for his attack, and stated that he could see clearly now - not the shield of Medusa nor Algol, but the power of Athena guiding him to victory, and unleashed his Rozan Shoryu Ha, defeating Algol. Shiryu stated as Algol fell that his actions were not just for the victory now, but also to protect his friends.

After Algol was defeated by Shiryu, the Saints Shun and Seiya turned back to normal.

Hades arc
Later, in the anime adaptation, Algol, along with Auriga Capella and Kerberos Dante, was resurrected from the dead by Hades. After being resurrected, all the three saints were using new cloths, the surplices, made of the same material of that of the specters. The new cloths look like the old Silver ones, except by the color, and perhaps they don't have the same powers, as Medusa Shield wasn't used or even commented at this time.

They were sent to kill Shiryu and Dohko. They arrived on the waterfall of the Rozan mountains to complete their mission. However, Dohko wasn't there, as he left to the Sanctuary to fight against the specters. They attacked Shiryu, and after a short period, Shiryu defeated all them with his Rozan Shoryu Ha.

After they were defeated, Shiryu left to the Sanctuary to help Dohko.

Although Algol's resurrection in the Hades arc was clearly depicted in the anime adaptation as a minor addition to the plot, Kurumada only hinted it in his manga with the open tombs of deceased Silver Saints.