It's not bad. I'd definitely rate it more highly than the soulless copypasted light novel adaptations that comprise what seems to be the bulk of the manga industry's output these days. There is at least has some ambition here.
That being said, it has the air of an author trying to make an ambitious work but not really having the talent to pull it off. For a self-described dark fantasy, it comes across as cartoonish. The characters lack depth and their actions and motivations are unconvincing. Hopefully the author will be able to add depth as the story progresses.
I worry they won't get the chance, however. It has the stench of early cancelation about it. It's difficult to describe why, but it lacks that crucial hook, that sense of coherence driving the reader forward. Reminds me of the many works where the author came up with the single cool idea or premise they needed to get their work serialized, but had no idea where to go from there.
Overall I would characterize this work as amateurish. If I had to guess I would say the author has mapped out the few major plot points, but is just making up the rest as they go along. It certainly reads like that is the case. It's about what one would expect from an author whose previous work was a light-hearted sports manga trying to make their own Berserk.
Yet I can't hate it. At least it tried, and there's still a chance for it to become something great.