Lymphocyte about 10 years ago I don't think so. His sideburns differ from Mukai's and I don't think he wears a belt either. Just something I've observed.
comicmonkey almost 8 years ago I checked the pixiv tags and it says アラド戦記 which is the japanese equivalent to Dungeon Fighter Online (at least according to wikipedia. I added the "Dungeon and Fighter" tag, but feel free to correct me if you think otherwise.