Looking for the manga where the mc gets kicked out of the demon lord's army for not having any magic. Only to find out later that it was all because he was a human and not a demon. (No physical differences between them).
He stays in the small (human) village that helped him after being kicked out,

where he became the next village leader. And helps out trying to bridge the demons and humans.

Later we find out that as a young child he was kiddnaped by a demon and later raised by one of the Four Generals.

Pretty sure it's this one.
Kaiko sareta Ankoku Heishi (30-dai) no Slow na Second Life

That's the one.
Thank you. ☺☺