I've read on to the next chapters, and I have a theory that this may have been written by an edgy teen.
The MC is an unknown hero somehow, despite the fact that every damn guard would know him, if not at least as a security matter.
The MC has super self doubts despite the fact that he apparently targeted multiple monsters surrounding a kingdom that just happened to attack right when he needed to prove himself. Then he used a technique that took out all of the monsters surrounding an entire kingdom that hit all of their vital spots.
We're not gonna touch on the generic female MC who was saved by him in her youth.
Later on they go to a town that apparently has no damage, but has been attacked by demons. This town is close to the capital, but apparently nobody noticed it being attacked. Then we finally see the demons and the dialogue drops to braindead levels.
"We'll fight you because we're heroes!"
"Grrr we're demons! We're gonna enslave you in the name of [insert generic demon name here]"
"Not on our watch, because we're heroes!"
"Gah! How can this be? I've been attacked from a great distance!"
And so on.....
It's just so cookie cutter and bland. Maybe it gets better down the line, but this is just..... yea not great.