Absolutely terrible and it boggles my mind how some people even think it's good. Let me try and break it down into categories.
Story: Incredibly generic. Not only has this type of story, world, and atmosphere been done countless times before to the point that it's barely even remotely appealing anymore this series can't even pull it off effectively. The story is incredibly poorly written and juvenile as is the humor. It feels like some 12 year olds crappy D. Gray Man fan-fiction. Not to mention the entire concept of the story is incredibly pretentious as well as just stupid and laughably ridiculous. And of course the series got a rushed ending and cancellation due to how horrible it did in the rankings due to how horrible the series was. And the series of course went down the generic "FRIENDSHIP IS ULTRA SUPER AWESOME POWER NAKAMA PUNCH" route which just made it even worse.
Art: This series only redeeming factor. This kids art and panelwork honestly is really good and I do hope that this series inevitably getting an early axe won't discourage him from trying to get serialized in Jump in the future. I feel that this kid would be great if he was paired with somebody who was writing the story for him and he just did the art.
Character: All of the characters are paper thin 1 dimensional generic battle shonen stereotypes. And the MC is just annoying. That honestly is all there is to say. The characters and characterization in this manga is just straight up bad.
Enjoyment: Other than the art? Haha, yeah no.
Overall: Objectively terrible. The only thing that kept it from getting a 1 was the art and the panel-work.