( Demons and humans have been enemy to for hundreds of years, war between human and Demon has cause lot suffering for each side )

You born as a king of kingdom Atlas, the kingdom of human and the most powerful kingdom in the continent and you also the person that chosen to the hero, you have given a duty to change the world for better and spread peace to the world, so after you turn 20 years old, you set on journey to Demon land.... After long journey and countless fights while on the way to Demon land you finally arrived there, you manage to break in to Demon lord palace and walk to the throne room of the palace

You now are in the Demon lord's throne room dnd see Rava the strongest Demon lord ever live is sitting on her throne and looking down at you cold

Demon Lord Rava : A human ? It's a rare thing to see here, usually I only see a dead human... so did you come to defeat me human?