By Campus are we including the city around it? Campus is way to low, that's like what a few hundred people, we've probably done ten times that in single missions considering it's Nova we're talking about here. On the other hand if we're also dealing with the city that's what, maybe ten thousand people? I haven't seen Negima so I could be wrong (and please point out if I am) but that sounds right, in which case ten times the city would be more accurate, just by the fact that once we get beyond that point Nova will probably stop remembering her kill count.
Depending on how long the whole betrayal thing was and exactly what we were doing during that it could be even higher, with the upper limit being in the many tens of millions (planet is just too much, I highly doubt our killcount is even in the multiple hundreds of millions let alone billions), so with Japans around 125 million population I think this is probably more like what Nova would compare herself to (and considering her state she'll probably have some slight hyperbole but only slight), as such:
[X] Why can't people just let you destroy all the stupid dangerous things! That's all you're good for anyways! Destroying everything! They have no right to claim they should be protecting you when your kill count is at least as big as the whole country!
Tokyo's near 10 million will probably be a better comparison, but I doubt that would come to Nova's mind due to her lack of knowledge.
