Honestly...I can see him clearing the city.
I don't even know what it takes to put him down for good.
1000 zombies = nothing
250 zombie dogs = nothing
150 crimson heads = a bit more annoying than actual zombies. He simply decapitates them.
30 giant spiders ( do you mean the boss one in RE?) = Dante can pull it off.
100 hunters = Dante will get hurt, but he can put them down.
50 lickers = same as above but with more difficulty.
10 Tyrants = TROUBLE. These guys can take a lot of damage and can still go. Ebony & Ivory will be useless. Alastor might hurt them a bit. I think he will have to devil trigger the crap out of them to pull it off.
1 Proto Tyrant(was that the one Rebecca killed/or Chris/Jill?) = don't remember much about it...but if it approaches Dante right after he (possibly) takes out the 10 tyrants Dante will have to retreat until he can regen himself or just put it down via Alastor. But honestly I don't remember this guy.
Nosferatu (was the guy from Code Veronica right?) = Not sure. In the game you needed a sniper...but perhaps Dante could well I don't know.
Queen Leech (CV right?) =I don't know. Perhaps Devil Trigger it for the win.
3 Nemesis = I assume they all have rockets...they are incredibly tough and smarter than Tyrants...ugh I dunno. If they manage to hit him with a rocket it is lights out for him. No way he can soak that damage after this terrific gauntlet.
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I am not 100% sure about this stuff.