Dropped at Chapter 39—however, I always appreciate the translators that take time out of their days to make this readable for us. Thank you all for your hard work.
I actually came into this thinking it was a different, similar manga—Nozomanu Fushi no Boukensha (which also isn't great, but we won't get into that here). And honestly I was shocked at how similar the two were, seeing as I didn't even realize they weren't the same thing until like, Chapter 15. That alone should be a testament on how cookie-cutter boring this one is. But that's not even my main problem with it, my main issue...
...is that it doesn't have a single core focus.
You'd hope that the progress of our MC's monster evolution would be the core focus, but no it seems like it's only used to stretch the plot out—there were numerous points where I assumed he would level up, only for him to be short 3 levels or something, and so a haphazard battle that takes up three chapters is thrown in.
So then you'd think it would be character development. Odd for this genre, but sure, I can see how it could be done well. But no again—the MC is framed as an edge-lord lone wolf but is an actual idiot and a loser. At no point was I rooting for this guy, and that sucks because obviously I want to root for the MC. The little sister is your typical, "I treat you like shit because I love you" trope that bombs everything it touches, then you've got your token anime Betrayal Backstory™ that adds literally nothing, you've got your air-headed love interest that only exists to be protected by the MC, and finally your bad guys that are bad because they're bad guys. And while we're on this, I hate that the only backstory we got was for the LEADER OF THE ACTUAL EVIL GANG. And they placed that shit right in the middle of the fight, presumably so that they could show the "Look and what happened to his Mom and Dad" illusion. sigh
So then what? Is the world the focus? Again, we're getting further and further from the norm, but a lot of fantasy stories have a rich world so I can see how it could be done well. BUT AGAIN, NOPE. All I know about this world is that there are dungeons, and occasionally monsters spill out... Other than that, it differs in no fundamental way from other fantasy manga. And even then, dungeons and monsters are not new concepts. It's a boring, flat world with nothing making it stand out.
So what's the core focus then? I genuinely have no idea. For the MC to become human again? Well no, since he has no problem throwing that goal away in the heat of the moment. And aside from "evolving" he does nothing else to try and aid himself in this goal.
In summary, 2/10—don't bother reading, it doesn't respect your time or your intelligence, and clearly just takes from already successful fantasy-evolution stories to sell copies.