The Demon Lord is The New Hero!?

Exhausted by the relentless defeat against so-called "Chosen Heroes" armed with sorrowful pasts, the reigning Demon Lord concluded a plan to ensure a winning chance.  A seer revealed the next Hero’s was born in Garia, it clicked to avoid death and to make world domination a success, he only got one plan. His brilliant scheme? Pose as a youth called Ren, slip into town, and gift the Hero a dull, contented upbringing filled with plenty of meals. So the hero does not have any motivation to wield a blade.  Not knowing that his action gonna make him become something else...