I'll just throw my piece here as well.
First of all, I love Vergil, therefore I might sound a bit biased, but I will try to refrain from doing so.
Vergil might be cruel, mean, cool, full of pride and many other things but certainly not evil.
However, not to confuse the issue, I am not saying he is actually good either. For me his case rests somewhere in the middle. The term "antihero" is pretty close to what Vergil is. From wiki: In
fiction, an
antihero (sometimes
antiheroine as feminine) is generally considered to be a
protagonist whose character is at least in some regards conspicuously contrary to that of the
archetypal hero, and is in some instances its
antithesis in which the character is generally useless at being a hero or heroine when they're supposed to be one. Some consider the word's meaning to be sufficiently broad as to additionally encompass the
antagonist who (in contrast to the archetypal villain) elicits considerable sympathy or admiration. The term dates to 1714, although literary criticism identifies the term in earlier literature.
To clarify some things, by hero I do not mean the person who saves the day, but the term in literature. In a few words I refer to the Main Character. Usually the main character in a game DOES actually save the day, but not in every game. Popular example is Kratos from God of War. Even when in the first game he was actually working to save the humans, he was doing it because he wanted to settle things with Ares and relieve himself of the nightmares he had. And even his way of saving the day was distorted. Sacrificing whoever stood in his way be it man or monster to achieve his goal. Kratos is a perfect antihero example. So is Gutts from the Anime/Manga/Game Berserk.
Clarification number two: I know that Vergil is not the Main Character of the game. However he is one of the main characters. His role is as important as Dante's is and without him the game wouldn't exist. That is why I considered the term antihero fitting for him.
Vergil is the typical antihero archetype that lusts for power and is willing to sacrifice everything and everyone in order to achieve that wish. Many popular Japanese characters share this lust, like Vegeta from Dragonball Z and Sasuke from Naruto. These characters kill and destroy without a care as long as their deeds bring them close to their original goal. In few lines, they go with "the ends justify the means". For them, their obsession with ultimate power is so great, that they are able to overlook every bad or otherwise unforgivable deed they do if it's for their goal. Does that make them evil?
If this was a D&D game I'd make Vergil's allignment Chaotic Neutral. From wiki again: Chaotic Neutral is called the "Anarchist" or "Free Spirit" alignment. A character of this alignment is an individualist who follows his or her own heart, and generally shirks rules and traditions. Although they promote the ideals of freedom, it is their own freedom that comes first. Good and Evil come second to their need to be free, and the only reliable thing about them is how totally unreliable they are. Chaotic Neutral characters are free-spirited and do not enjoy the unnecessary suffering of others, but if they join a team, it is because that team's goals happen to coincide with their own at the moment. They invariably resent taking orders and can be very selfish in their pursuit of personal goals. A Chaotic Neutral character does not have to be an aimless wanderer; they may have a specific goal in mind, but their methods of achieving that goal are often disorganized, unorthodox, or entirely unpredictable.
Vergil fits completely with this description. He is completely free. Nowhere bound by anything, neither family ties neither any particular enemy. He follows his own heart, his own rules if you prefer in doing things. He shuns outside rules and just does what HE thinks is right. The most obvious example is that he will not use guns as a personal rule. Good and Evil come second in his mind. He just does what needs to be done to achieve his goal. He prefers working alone, and only teamed-up with Arkham because they both wanted to open the gate to the Demon World. However, he never saw Arkham as a friend or a partner, just someone that would help him reach his goal faster, otherwise he wouldn't have teamed-up with him. He is very selfish with a very specific goal in mind (power) and his methods of achieving that are unpredictable. He clearly holds no love for demons - he killed both Beowulf and Hell Vanguard mercilessly - yet holds some respect for the species as a whole since his father was one - thus he preferred staying in the Demon World instead of staying to Earth.
Guys like Vergil are really dangerous because they never stop thinking about their ambition. They have a one-track mind until they have realized that and will perform cruel and evil acts with no remorse. However they are not evil by nature. Someone evil does Evil stuff because he enjoys it. Because he likes making others feel miserable. Etc. Lord Voldemort is Evil. Freezer is Evil and Sauron is Evil. But not Vergil in my opinion.
