Think about it logically. You'd have to face him like a Boss, because killing him would be too far-fetched. Dante fights the likes of Mundus as his Boss, he kills Frosts like their nothing. You would have to have a small pack of demon enemies, each one upgraded. The battle would be tough, but you should be able to win eventually. They would fight humans as their main enemy. Dante, Nero, Lady, Trish and maybe even Vergil as their Bosses. As for any other enemies, I am lost for thought.