Hm... a different take on isekai huh. And unlike most isekai where they punt on Goblins as easy enemies, they're choosing to make the goblins on a completely different level. Interesting. Also, mom okay?
I fucking hate when Isekai authors make the residents of the world stupid and technology behind where it would be compared to other things just so they can arbitrarily make the MC seem more impressive. You're really telling me this person has never heard of stitches and can't even conceptualize why closing a wound might be beneficial? They're still a fucking human, not a newt.
That’s because Japanese has a whole slew of words starting ma (魔) that refer to various magical and/or evil things. In this case magic is mahou (魔法) and “magical creature” is mamono (魔物) which in a lot of fantasy stories is rendered as monster or demon.
If you remember, in chapter 1 Shion asked if **ma**mono existed (rendered at the time as “demon” by this very group) so he was sure that **ma**hou must also exist but his father did not recognise the word.