@Joonhas we have already seen that he cares about the people around him to a crazy extent when that same guy started to disrespect his familiar
it probably has something to do with his backstory that we have yet to see
@chucke1992
It's also my first time seeing it being mentioned in an isekai, but I always apply it to other isekais even if I know deep down it doesn't work like that for them
@Koremitsu_Arita
come up with the techniques, fight yourself, improve
we don't know if the shadow that he fought was an exact replica of himself or not so for all we know it could have actually been acting by itself more than shadowing him