Artist.
Pen-name: カトゥ (the artist always uses this spelling: "katwu")
Circle & site name: 幻想忍者屋敷 (Gensou Ninja Yashiki)
Old site name: カトゥの忍者屋敷
https://www.pixiv.net/users/32998
https://www.pixiv.net/stacc/genin
https://twitter.com/katwu_h
https://twitter.com/intent/user?user_id=728074790141988864
https://sketch.pixiv.net/@genin
http://www02.geocities.co.jp/AnimeComic-White/9321/
http://www.geocities.jp/gensou_ninja/