In DMC 1, Dante wanted to stop Mundus from invading the human world. But why were demons evil? Why was it bad for them to inhabit the Earth? Their ugliness? Scariness? No. They had evil goals.
Did Mundus want to wipe out the entire human race, or just subjugate them somehow?
How could demons/devils invade the entire world? What was their intention?
Again, video game stories are usually filled with plot holes...
"IN THE BEGINNING THERE WAS A WAR. BETWEEN THE HUMAN WORLD AND THE OTHER, THE UNDERWORLD. BUT SOMEBODY FROM THE UNDERWORLD WOKE UP TO JUSTICE, AND STOOD UP AGAINST THIS LEGION"
And
MUNDUS: "I will return, and I will rule this world"
Tells you:
a) Mundus wants to rule the human world by force (i.e. against their will)
b) The use of the word 'justice' implies he was unjust in his methods, therefore 'evil' by human standards
c) The fact there was a war which he lost and he wants to return, implies a 'vendetta' against humans for it
d) The use of the word 'rule' seems to imply he wants to enslave humans rather than destroy them and their world
e) By saying "this world" and not "the world" he sort of implies he wants to annex the Human World to his own; he wants to conquer it and be its 'Emperor', as he already is in the Demon World (or return it to the state of being his if it was so originally)
It's implied in the manga (if you consider that canon) that demons already ruled the human world in "the beginning", where humans were slaves; Sparda fought the demons off and separated the two worlds so that humans could be free. According to the canon of the first game's intro though, we don't know if there was a war as a result of a rebellion by humans, or that the war was an invasion of the human world. But we do know that demons were in the human world, and because demons are evidently stronger than humans, they needed a saviour like Sparda to save them. So yes, demons invaded the entire world and Sparda kicked them out again— we just don't know the details of how that happened.
Why are demons evil? It's moot in the game— I personally think the concept of 'evil' is there as a human perception of demon life, not a real state (because in the games 1-4 at least there are no 'angels' or 'good' counterparts to the 'evil' demons, nobody to have 'created' them, no antithesis for them but Sparda himself, who is also one of them). While there are things like 'ignis fatuus' or 'holy water' and stuff like that that pertain to more religious ideas of good and evil, it seems to me that there was no absolute 'good' or 'evil' really pushed (no God or Satan figures as such, Mundus is just the 'devil king' and Sparda may be a Jesus figure but he is also a devil); and demons simply worshipped the ideals of strength, fleshly desires, oppress the weak and obey the strong, etc.
From what I can gather, it's an amalgam. The fact Dante is half devil and yet is a good guy somewhat proves that good and evil are nebulous concepts in this game series, and that you are meant to accept that. I think we regard the demons as 'evil' but they are just ruthless and power-hungry creatures, some that enjoy the suffering of others, even their own. Perhaps a sort of supernatural self-proclaimed 'master race' rather than anything irredeemably "evil" by nature. After all, Vergil is not completely evil and has a sense of honour about him, Beowulf appears to value the concept of loyalty and is upset for being betrayed by Sparda, and Sparda himself became empathetic and compassionate, etc.
The demons are 'evil' as far as humans are concerned, but I don't think they are as such. They're just another form of life in the game universe, a (generally) more cruel and predatory form than humans are.
Compassion or
empathy appears to be what separates humans from devils in this game universe, and Sparda from his own kind, redefining him as a hero to humans.
LADY says it best:
"There are humans as evil as any devil, as well as kind and compassionate demons in this universe." As in, she was wrong to assume they were all just pure evil.
DmC may throw all of this out of the window with its 'angels' and Lilith and Mundus indicated to be Satan and whatever else, but we're in the main Devil May Cry board here and I'm not going into whatever DmC may or may not be. I'm not considering it a true Devil May Cry game at this point.
