Now, this manga I would not reccomend reading. It may seem like an interesting one at first, but it winds up mostly being cliche, cheesey, and in my opinion, boring.
I was feeling pretty meh on the story. Not that good, not terrible either. It is the cliche, 'Hero sent out to kill terrifying monster, but won't for some reason or another.' I really didn't like it, but maybe it is just personal opinion?
Art, oh God, the art. My opinion is that art is usually personal opinion, but I am confident that you would share this opinion. The art let me down. A lot. I hated it. The eyes on every character look messed up, they change looks and are at the same time hard to tell apart, some of them even seem to be wearing lipstick in one frame and none in the next. The only thing that keeps art from being absolutly terrible is really the detail. When fighting Copi V2 (Copy's failed Copy) You can see the gruesome veins in the tendrils and blood is very well used. But that is about it.
Also a bit meh. I really didn't feel it. Cliche hero, cliche badass right hand man, cliche quiet girl who yearns for main character to notice her, and cliche new girl who snatches the main character away. The only twist is the whole demon queen, 'Hey, I'm going to travel with you now!' So about an average meh.
My advice? Don't read this. Look for maybe Id, the best thing ever created or another fantasy genre.