It's honestly a great story for what it is, but it feels like it doesn't understand its own genre. That's not necessarily the worst thing, but the story does seem to suffer a bit because of that.
For example, the hero party goes everywhere looking for artifacts and trying to level up to face the current demon king. But in an attempt to keep the story in the location the main character (MC) settled down in, everything important seems to be set within a day's walking distance from one location.
There's this huge world and impressive ruins and history and yet it all comes back to this frontier town (a frontier to the edge of known civilization, not the actual demon threat).
The characters are interesting, and the art is appealing (if a little rough at times). The plot is nice, and I love some of the concepts its attempting to deal with.
And everything, despite its shrinking scope, is handled well for the most part. Even the genre shifts are handled as well as they could be despite holding the story back overall.
I would warn there's (so far) one panel of detailed nudity and a handful that come close, and there's definitely things kids shouldn't read besides that.
Overall, it feels like it could be so much better, but is still well above average.
Edit:
The review above me, while I don't completely agree with everything that was pointed out, does tell a lot of truth. This story's greatest weakness is it's lack of a solid identity (genre confusion), which results in the main characters ignoring the needs of the rest of the world. It really does make them look selfish in a way it wouldn't if this story had a solid identity.
But, where I do push back is on the little sister's decision. Yes, the MC and the FMC are absurdly unconcerned for the rest of the world. But it does make sense for the little sister to make that decision:
The little sister is forced, against her will, to endure
a companion so terrible he ends up destroying the hero's party. She hates him with all of her being, and he's trying to manipulate her into being his wife. And she isn't allowed to kill him the way she can most of her other problems.
In fact, she splatters him on the wall of her room before being forced to heal him against her will.
She's given up because that one despicable companion has demoralized her to the point of giving up. Imagine, a teenage girl surrounded by people she can't connect with and forced to be with someone she hates, giving up on the thing that makes her so miserable because maybe she does want to see the world burn a little at that low point in her life.
What should happen is the MC and FMC start helping her form a new party, and the fact they don't is why I do agree with a lot of what the review above says.
The MC and FMC are absolutely illogical or selfish when it comes to the fate of the world.
I just don't feel this particular story suffers that much from this one illogical point to say it's bad overall, because the story isn't about saving the world.