holy crap i just thought of this (this is not intended to be offensive towards any religious groups). what if mundus is god and sparda/dante/vergil are lucifer. think about it. mundus has control over humanity and though he is not directly doing anything to humans, he is swaying them with influence (like how we don't see angels or demons but they are manipulating out thought process). sparda, didn't agree with the way the demon king ran things, and he rebelled. his punishment was banishment. much like god and lucifer. dante and vergil represent two traits of lucifer: active rebellion, and cunning. the end of the game represents the apocalypse. the revelation of angels and demons. plus, the side plots of mundus seeing a mixed breed as a threat and an abomination. so he had them all slain. and if you speak out against him or his teachings, he will damn you to eternal pain. yet he still claims to have use for you and your burning soul.