First half of the first volume (~80 pages) is some generic stuff with Magic, Heroes and Demon Lords. You can just skim through it - nothing interesting, not worth reading. Now what comes after that is the fun part when the story actually begins. It is not an isekai, and not a power fantasy. It is a good story of surviving against the odds with a lot of cool moments. This is a story about a world(s) (there is a distinct MC, but the story does not focus on him much), and it is a pretty good written. Also, good art. There is no message tothe whole thing (aside from the usual "never give up" and "there is always a bigger fish") so it does not go past 8 in my opinion. Also, not much of in booba (or any fanservice) department, but, well, maybe it is not needed here. So yeah, pretty good story with wild battles.