I don't find it too hard to believe. See people crazy about what I did in WKC, but that's just normal business for me. I can't do the same with comics as I just get sick of reading at some point, but I'm not surprised that some did it in 5 days. It's like my friend who watched like 400 episodes of One Piece in a 2 week span.
--
http://i.imgur.com/4KfnE.png
http://www.yourgamercards.net/trophy/a/CaptainRockman.png