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?
But to answer the question in your blurb, maybe to get genuine love I would fall for a person even if he doesn't exist in our world. Really interesting story ??