This is Natsume, who plays a small role in '9th Order'. He's the owner of a manga shop, aptly names "Natsume's", which Daigoro loves to hang around in. He and Natsume are pretty good friends, despite the age gap, and both love manga.
Just in case you're mental and think I do, I naturally don't own any of the pre-existing series featured in this piece, as well as K-ON!! and Shonen Jump (but sweet Jesus if I did I'd tell everybody about it). On that note, I'm upset that I had to cut Ritsu's face out of that picture, coz, y'know, she's HAWT ¬¬
Unfortunately, despite him being my best designed and favourite character, has been cut from '9th Order'. In theory, if I turned it into a series he'd rock up in, say, chapter three or so.