Here, Humans can get what he just did and demons can use mana / magic. Period. There are no exceptions, other than if you really want to delve into which races are considered demons or not, since I believe not all races that are under demons' control can use magic.
As for how a human came to do what he did... there are reasons, spoiler reasons.
Thanks for the chapter. I guess her dad was suspicious of anyone comes to the village who isn't known. You can have the mark without being an adventurer I bet. Wonder what happens to demons who get it besides being attacked by humans
@JKTV
From memory it should happen fast
Just bear the headache to machine translate the wn if you can t wait and on cover ln vol2 you see him holding a baby, it should happen after 1st mithril ore mine event