Apparently the bible also promises the deaths of pretty much everyone now living, roughly 7 billion.
And then, in 1000-ish years everyone who gets through that (or is resurected or born or whatever, ie: a lot of people) but dosn't like the rules in Paradise gets done in too. If Paradise is run along JW rules, then probably a lot of people won't like Paradise: so lots more killings to come then.
Not that they're human, but I think there's also something about the demons being burned alive at the same time - there might be a lot of them.
Nothing like a good mass killing to show the Supreme Being to be the Almighty.