Docrates was a saint in the XX Century, and Cassios older brother.Ikki and other saints have known about his power.
Theft of the cloth
Docrates and his servants stolen the Sagittarius gold Cloth, but Ikki give the helmet (that he kept) to Seiya when he converts himself to the good side. Docrates destroy the place, killing Ikki (already weak after the battle with Seiya), that was buried by the landslide caused by Docrates.
Capture of Saori Kido
After giving the Sagitarius cloth to the pope, Docrates goes capture the helmet of the cloth, but when the police arrives, with anhonorable sense, gets away with no fight, but kidnaps Saori Kido to don't lose the opportunity to get the helmet; he will give back Saori in the Graad Coliseum, in exchange of the helmet, far from the police.
After, in the Coliseum, Docrates reveals want to kill Seiya and rip out his ear, to avenge his brother. With Hyoga help, Docrates was defeated by Seiya and Shun.