Issei the wielder of Ladon

I suck at summaries so the story is about Issei who finds at a young age that he has over one hundred different minds within his head because he wields the lost Longinus that holds Ladon the mythical dragon which Hercules had supposedly slain. How will Issei's journey differ with these guiding voices. Of course it wouldn't be Issei without his Harem but with a few girls added on.