(That's a shame, it's like Attack on Titan past Return to Shiganshina arc, there's just a lot of potential for world building, but instead of constructing on the massive worldbuilding, exploring the world in AoT, everything just narrowed down into war between nations or Eldian vs Marley. And Isayama doesn't even bother tell us anything about other nations, the world situation, it's just Eldian vs Marleyan, Paradis vs Marley all the time.)

This series handles power creep pretty bad. In volume 13 or so, Bell is already level 4 when the rest of the party is still level 2 or even level 1. I think up until vol 15, he's even at the near end of level 4, from just how crazy his battle with Juggernaut. Bell is just progressing too fast. At this pace, if the party's development rate is just as normal as most normal adventurers do, then the gap is just too big and honestly I just don't know what they're gonna do late in the story.

in like vol 13 & 14, the author just straightly abused his own power system that he himself created. I remember someone said that only Ottar's shockwaves is able to defeat level 4 monsters. And I confirmed it myself by reading Familia Chronicles. But how the party managed to survive the rampage from a level 6 monster Amphisbaena is just beyond my understanding.

First of all, the average level in that party is level 2 or 3 with Aisha being level 4. Haruhime has this level boosting ability, but even that has limited use and only boosted your level by 1. And Bell is not even there. How everyone survived with no death is just ridiculous. There is a literal level 1 & 2 there fighting against level 6 gigantic monster. Following that Ottar's battle logic they shouldn't even survived, at all.

I mean, it's Freya. She deemed his soul as pure and then proceed to disguise herself as Syr in order to get close with Bell. And you know the rest.