That "Hero" is too hateable, and narrow sighted to enjoy having around for even a panel. Like how the fuck are you going to become the "Final Hero", if you don't end the conflict between humans and demons? So long as both sides continues living, the conflict will continue without end, leading to the necessity of the Hero for generations to come to counter future Demon Kings. Your superior had the right idea, by trying to bring an end to the conflict itself. But no, you had to brand your superior as a traitor, just so that you could fulfill the tired route of this endless conflict, and ensure that you can't be the "Final Hero" for humanity. At this point, the only way you are going to be the "Final Hero", is by being exposed for your sociopathy, and forever stain the title of Hero.
Also I'm sick and tired of these mangas that are nothing more than advertisements for LNs. If anything, this lessens income (If the series is earning enough to begin with). As the manga serialization of a series can serve as a second income source for the series. With the major addition to expenses, being from the mangakas (If anything, considering how little they are actually payed for their work) doing the illustration for these series, to fit with the written story. I cannot understand, that if this series is based on an existing LN, that has enough traction to get a serialization, can't hold onto this revenue.