*Minor spoilers ahead*
'My Capricorn friend' is a story about guiltiness and freedom of choice. It is not by far one of the best one-volume mangas I have read, but it isn't so bad as to not give it a try.
Since the synopsis in mal is so brief I'm gonna explain a little bit more about the plot: the mc, Yuya Matsuda is really aware that school bullying surrounds him. But since he has neither the role of the bully or the victim, he is unable to step in that world or even try to do something to improve the situations he witnesses at school.
One night by chance he finds out that Wakatsuki, one of his bullied classmates, has killed his bully.
So my review is going to be brief: this is a manga that could have transmitted so much but in the end it didn't. This story at first is really approaching and in fact it is, but the characters sometimes suck. The mc is cold as ice most of the time, to the extent it gives off that feeling that he has been through the worst things in life. I would have liked him to act in a more humane way. And also I think that some characters that had been almost transparent gain a lot importance so the story could end.. making some sense and being a little bit too dramatic. The art is worth mentioning: amazing scenery and backgrounds. I just wish the panels had had some more dynamism. The most cool thing about this manga is that magic aura that has sometimes.
So, overall: well, it can be read in less than an hour so it is not a waste of time. Not awesome but it is interesting, easy to read exciting sometimes. And I don't know why this manga is so unpopular since it has even been released in Spain! So give it a look if you have time :D