日向悠二 (Himukai Yuji)’s most notable work were his character designs for the 世界樹の迷宮 (Etrian Odyssey) games, and has also worked on an anime called 吉永さん家のガーゴイル (Yoshinaga-san’chi no Gargoyle). He also sometimes does illustrations for various videogame and light novel magazines. As well, he used to do a lot of doujin work, and his circle name was 地下魚！(ungrofish!)
His website used to be updated frequently with pictures of his customized figures (!!!), as well as fanart and other awesome illustrations, but beginning in 2009 he has switched to Twitter completely for updating. (His old archives are still on his website though)
His art style is immediately recognizable, since he uses a shiny and vibrant colouring style with solid shadows, and his characters usually have round faces and huge eyes that aren’t as detailed as most of the ones seen in anime art today. Also, his lineart is impeccably clean, so if you see some bold lines and colours, it is most likely Himukai’s work!
Himukai Yuji @ Doujinshi DB: http://doujinshi.mugimugi.org/author/2842/Himukai-Yuji/