User blog comment:B214/Volume 22 spoilers/@comment-50.181.99.189-20161223042942/@comment-29963364-20161223075805

That's part of what makes them such great/popular characters.

It hypes up the audience,  makes them expect great things from the MC's,  and gets them engaged in their story.

I get that MC's having epic back-stories can make them rather dull. But that's only the feeling you get "after the fact." A person can have the greatest back-story ever, but if they aren't great themselves, then non of that matters.

What makes an MC great isn't their back-story. It's the actions they themselves take that make them great.

As an example:

Monkey D. Luffy


 * Is the grand-son of a Navy Admiral (Monkey D. Garp).


 * The son of the Leader of the Revolutionary Army (Monkey D. Dragon).


 * Is one of the people who have the letter "D" in their names.

But Luffy is just a goofy kid who wants to live a free life on the sea. He loves to have fun, loves to eat, and will fight like hell for his friends. Luffy was a great character, and fans loved even before we learned his back-story, so it doesn't (and shouldn't) have any negative affects on his quality as a character.

The same should be the case for Issei if his back-story was actually interesting/epic.