this is so good, it's only in the 14th chapter that we get some more insight, so don't be fooled by the low rating guys, it's mostly just people who didn't give it a proper read or couldn't stomach bullying. So far it's definitely the most realistic manga to tackle the issue of bullying and it has a deep plot as well, the characters are also very complex, only one of the characters is truly one dimensional the rest all have layers so please do give this a shot before dropping it and lowering the score further
so far a solid 8.5/10 could be higher but it all depends on how it's resolved and whether the characters become redeemable