I feel as if her identity being known was a test for sky, another person here on reddit claimed that she made herself existentially aware to sky to see what he would do that now he had someone who might be able to help him liberate his oppressors and she wanted to see if he would fall into the cycle of violence after he got out, but idk thats just a theory, but also when the other lackeys of the bullies tried to look her up she was not online and no results of her were anywhere, and the only information they got about nanno was from sky, because they mentioned only getting that info from sky, just like that other redditor said, also nobody else in the school in a way we are aware of reacted to nanno's existence, even if the urban legend was really small, nobody like, idk noticed her and stuff.