This feels weird, as if the author is rushing to make a climatic final battle.
Yet the raws are at ch 41. They are still fighting this dude in a final boss level battle, no idea how the author plans to up the scales after this with how much of a threat this demon dude is being shown as. They are doing power of friendship thing and everything just to try to bring him down, even the protag is struggling against him. Might just be that the author jumped the threat levels of what is supposed to be just a lesser villain too much.