Talk:Takaaki Katagiri/@comment-89.152.149.48-20141109195509/@comment-856627-20141109223956

Well, it's very common for anime fillers/extras to become canon to the original manga (in anime adaptations of mangas, that is).

Like in Love Hina, where most of the anime's filler stuff became canon in the manga, or in Naruto, where Raiga Kurosuki and his Swords (which were used by Ameyuri Ringo) appeared in the manga.