A classic tale of a summoned hero.
A classic tale of defeating the evil demon lord.

...but what if the demon lord loved peace? What if the demon lord didn't know he was supposedly gathering an army to invade other lands, until one of his loyal subjects told him about a rumour like that circulating around in their capital and causing panick about a summoned hero within the public?
What is a demon lord to do?

Meet the Hero: the alpha bitch clarinetist
Meet the Demon Lord: the nerdy mathematician

A start of a very unlikely tale.