Nero didn't know what Teacher Prin… or rather, Mister Death, took out in front of her.
She just intuitively felt that this black-covered book carried an extremely strange power—note, this strangeness was something that even she, as a Black soul envoy, felt was bizarre.
But this obviously wouldn't make Nero back down… Some traits have been cultivated for a long time and don't truly change overnight—perhaps the additional traits she has now might have originally existed but were always hidden.
She might not even be aware herself… just simply felt comfortable—and perhaps she does know, which is why she follows her gut more, always letting her interests guide her.
Prin actually misunderstood something—Nero likes to fight, not because she needs to use combat as a reason for existence, but because she genuinely likes to brawl.
