Docrates is a character created exclusively for the anime adaptation of Knights of the Zodiac, known in its original Japanese version as Saint Seiya. He does not appear in the original manga by Masami Kurumada and was introduced by screenwriter Takao Koyama to expand the storyline following the battle against the Black Saints. Docrates is a colossal warrior of imposing size, often noted for his immense physical strength and stature, which towers over most other characters. He is originally from Greece and trained at the Sanctuary of Athena before being sent to Japan on a critical mission. A significant aspect of his backstory is his identity as the older brother of Cassios, the rival of Pegasus Seiya who sought to earn the Pegasus Bronze Cloth. This family connection fuels his personal grudge against Seiya.

In terms of personality, Docrates is cold, aggressive, and filled with malice. He is extremely proud of his power and does not hesitate to display it to intimidate his enemies. However, he also demonstrates a cunning and dishonorable side, as he is willing to take innocent hostages, such as Saori Kido, to achieve his goals and does not feel bound by his own promises. His primary motivation is to capture the Sagittarius Gold Cloth for the Sanctuary's Pope. While his official mission is to retrieve the armor, he is also driven by a desire for revenge, seeking to punish Seiya for the humiliation and failure suffered by his younger brother, Cassios.

Within the story, Docrates serves as a formidable antagonist during the Sanctuary arc. He is dispatched by Gigas, the Pope's aide, immediately after the defeat of Phoenix Ikki. His role is to recover the pieces of the Sagittarius Gold Cloth, specifically the helmet that remains in the possession of the Bronze Saints. His appearance marks a bridge between the battle against the Black Saints and the subsequent arrival of the Silver Saints, creating an anime-original narrative sequence. Docrates leads a group of loyal subordinates who wear dark, simplified versions of his own armor and assist him in combat and in securing the Gold Cloth pieces.

Key relationships define his actions. His most prominent link is with his brother, Cassios, whose perceived disgrace at the hands of Seiya drives Docrates's vendetta. He is a direct adversary to the five main Bronze Saints, particularly Seiya, Hyoga of Cygnus, and Shun of Andromeda. He also has a brief but pivotal interaction with Ikki, who initially sacrifices himself in an avalanche to stop Docrates, only for the giant to survive. His employer is the Pope of Sanctuary, but he takes direct orders from Gigas.

Docrates shows little character development, remaining a relentless physical threat throughout his appearance. He does not repent or change his methods; his arc concludes with his defeat and death in the ruins of the Galaxian Wars arena after a prolonged battle. His demise requires the combined effort of several Bronze Saints, as Hyoga freezes his legs to immobilize him, allowing Seiya and Shun to land the final, decisive attacks.

Notable abilities center on his brute force and his signature technique. While Docrates wears a protective armor that visually resembles a monstrous creature with multiple heads, he is not officially classified under a specific constellation, unlike most Saints. His most powerful attack is the Heracles Mōshū Ken, or Heracles Onslaught Fist. To perform this, Docrates concentrates his cosmos into his fists and unleashes two powerful, destructive energy blasts that create massive shockwaves and craters, capable of leveling buildings and overwhelming his opponents. He also possesses retractable steel blades within his gauntlets, which he uses as a weapon to try and finish off his enemies at close range. His immense physical resilience allows him to survive being buried under tons of rock and to break free from Shun's Nebula Chain with little effort.