This route is unlocked by either impressing Naoya when he tasks you to defeat demons for him or by revealing the COMP factory to Kaido. The Naoya route involves the protagonist defeating all Bels and becoming the King of Bel, meaning the overlord, seizing control over all the demons, and eventually fighting god in post-game events. It is revealed that Naoya's motivation for this course of action stems from him wanting to take revenge on God for his infinite reincarnation as Cain, the first murderer in history, the one who killed Abel, the first victim.