tl;dr: A story about a psychopath teacher acting like a psychopath and... that’s it. 

This manga starts off feeling a bit like a story about a teacher that uses irregular means in order to help his students but truly does have the goal of helping his students, kind of like a darker version of GTO. However, it quickly becomes obvious that isn’t the case at all and that the teacher is simply a horrible person that only cares about himself and only manipulates things for his own pleasure. To a degree there’s at least something kind of interesting there in that the manipulations do have some thought put behind them and do proceed in a pretty intelligent manner.

However, at some point things jump the shark and the teacher simply resolves everything through murder, at which point it's revealed that he’s already killed quite a few people before where the manga began. Once this happens there’s very little thought to most anything. There’s some manipulation and intrigue, but it’s pretty weak and really not enough to hold up the manga. It’s basically just a B-movie horror flick. Such stories do have value, but here with the killer being just as focused on as the victims the whole dynamic didn’t really work and largely it felt like there was supposed to be something more but just wasn’t.

I guess to a degree the narrative tries to develop the teacher’s character as well as some of the students characters, but in the end none of them felt like they had enough to them. The teacher is a killer so he’s a terrible person and thus hateable to a degree, and the students didn’t do anything wrong and are hence pitiable and hence likable to a degree, but beyond that there wasn’t much and hence investment in characters wasn’t enough to hold up the manga either. The attempts at fleshing out the teacher felt especially pointless as he basically just comes out to be a standard psycopathic serial killer without any more to him. In terms of the ending, it wasn’t satisfying, but really what type of ending could be satisfying. After they've done a certain amount of damage, whether they get caught or not, does it really matter? The entire things felt like a pointless mess.