Cerceus, also known as Selseus, is a deity in the Divine Realm bearing the epithet Divine Blade for his mastery of swordsmanship. He possesses a brawny, muscular build befitting his role as a martial trainer. Initially assigned as both instructor and sparring partner to the hero Seiya Ryuuguuin, Cerceus dedicated himself to refining Seiya's combat prowess. However, Seiya's intense training regimen and swift skill progression rapidly overwhelmed Cerceus, driving him to physical exhaustion. This led Cerceus to actively evade further sessions, including hiding to avoid the hero's persistent demands for additional training.

His interactions underscore a clash between divine tradition and human tenacity, as Cerceus's conventional teaching methods proved insufficient against Seiya's extreme dedication. The character remains defined by his Divine Blade title and his comedic training dynamic with the protagonist, with no significant personal history, development, or broader narrative involvement documented beyond this role.