Hypnos is a major antagonist of the Saint Seiya franchise. He's the god of sleep who resides in the Elysium. He's one of the two most loyal and powerful servants of the god of the underworld Hades, helping him in his purpose to wipe out humanity and take control of the earth. He is calm collected, cold and intelligent

Thanatos is the second major antagonist and is the brother of hypnos, he is the god of death and is ruthless and unforgiving, and has a hate for mortals, he is crazier than Hypnos