That was only for volume 5, imo author really liked to remind the readers that Arc was really normal dude, aimless, lack of combat skills, experiences and warrior mentality etc. So the girls mostly ended up as the one with the goals. Of course it didn't help that he was 'cursed' most of the time. Still a nice series since there is no harem or what so ever. Oh I think Arc now has a goal considering the events of volume 6,7.
As for last boss WN translation is starting, it needs at least 20 chapters to get rolling though. Otherwise it looks like a normal isekai aside from occasional identity crisis MC is having.