Information on the character Hades from the 1981 anime Ulysses 31 is limited to his role in the final episode of the series. He is depicted as the god of death and the ruler of his namesake kingdom, the destination Ulysses was cursed by Zeus to find. His portrayal mostly avoids the common fictional trope of casting the god of the underworld as a villainous figure, instead aligning more closely with his function in classical mythology as a solemn and authoritative cosmic entity.

In the narrative, Hades serves as the arbiter of the final trial orchestrated by the Olympian gods. When Ulysses and his companions finally reach the Kingdom of Hades, the god confronts the hero with a decisive choice. Hades declares that Ulysses will be permitted to return to Earth, but only on the condition that he abandons all his companions. He further elaborates that Ulysses must leave behind his son Telemachus, the alien girl Yumi, and every other member of his crew, who remain in a state of suspended animation. This offer represents the culmination of the many tests and temptations placed before Ulysses throughout his long journey. True to his nature as a powerful deity, when Ulysses refuses to accept this condition, Hades demonstrates his authority by turning the hero to stone. This act, however, is ultimately revealed to be part of the gods' secret test of character, and Ulysses is restored once he proves his unwavering loyalty to his crew. No information is available on Hades's background, personal motivations, development, or specific abilities beyond this final judgment and the power to petrify.