I gotta say, the premise for this one is reeeeally stupid. I mean, if you're going for a twist where there is no demon king, great. But if you combine it with the whole "slice of life" thing they're setting up, there's no conflict. Why should I be invested in this guy when the world is literally peaceful? There's no real incentive for improving himself, and even him meeting the heroine was just bumping into her more than anything else.
I hope it has some sort of twist that can make this interesting. That said, given the track record for these sorts of WNs, I doubt it.