The Demon King and the Evil Dragon Are Saving the World?!

Gu Weigu, a boy who had always dreamed of becoming a hero and indulged in chuunibyou antics, finally transmigrated to another world one day, just as he wished. But of the people summoned to become heroes, it was his younger sister who was chosen, not him! Unable to become a hero, the male lead accidentally acquired a seed of the Demon King's power and met a girl who was the incarnation of an evil dragon. The two somehow reached an agreement: they would trick his sister, the reluctant hero, into going after the current Demon King?! And so begins a hilarious adventure in which the de-leveled former villains travel together with the hero, trading sarcastic remarks along the way.