These "the original protagonist is actually an arsehole" plot stories are getting kinda stale, I like the rest of the story but I'd really like to have a baddie that wasn't just "destined".
I don't remember too well, but there
was some reason for that to be the case much further in the story of the light novel.
But speaking on a meta level, your comment made me think on how this trope and many others that we see in manga nowadays, were actually proliferated many years ago in web novels, that were later adapted to light novels, which we see nowadays being adapted to manga and even anime.
It makes me wonder what new tropes web novels authors are overusing nowadays that we'll be seeing years from now all over manga and anime.