Need help with finding a manga

I remember so much about it, but I can't seem to find it anywhere. MC can craft items heroes from another world used, but his country (father included) only cares about power, so his father gives him to the demons as a gift/sacrifice. Turns out the demons are chill and think that he is just an ambassador/guest. He makes items for them and massively overestimates their purpose in the heroes' world. (IE: turning a laser pointer used in "presentations" into an actual laser used to "make examples out of people" or something along those lines.) Also the Demon lord is secretly a little girl, who could have seen that coming.