Reminds me of a doujin I once read, except in that one the Hero turns out to be a pretty sick scumbag that uses his enslaved demon lord like a cum sock and even whores out the demon lord's generals and champions to what remains of his party.
I like this version better, because you can choose to totally not be 'that guy' and be nice to her.
Spelling and grammar need a bit of work, but for the most part I'm going to give this a watch.
And, you know what, seeing as how this a fledgling start up, I'll toss it some bucks.