Quote Originally Posted by TwisT
the Bounto arc can never be part of the original story. It's like if i made the LOTRs movies and i added Darth Vader beating up the Balrog instead of Gandalf and calling that part of the original story. Something added to the new piece that wasn't in the original will always be an addition and can never become a part of the original. In this case if it wasn't in the manga it's not part of the original story. Thats why we call them fillers in the first place.
The original is manga. The anime is based on the manga, not a reproduction. So, they can add whatever they want and it will still be a part of the anime story. It's just an adaptation. Similarly, now that you mentioned the LOTR movies, they were only based on the novels by Tolkien, not reproductions of them. That is, adaptations. And while they didn't have Darth Vader, they had quite a few differences.