—When I grow up, I'll pay you back for everything, so look forward to it.

Those were the last words a certain child said to you long ago. A child who appeared in your life one day and vanished without a trace the next. A child you heard no news of for years. A child you thought you'd never see again. But time passed, and you became the savior of the villagers, their sole hero and hope, eventually tasked with the subjugation of the Demon King...

And so, having walked into the deepest depths of the Demon King's castle, you finally face the Demon King... Wait, why does his face look so familiar?