Artist.
Nickname: kuuichi09 (くーいちまるきゅー, Kuuichi Marukyuu)
Circle & old site name: 揺れる猫機械 (Yureru Neko-kikai)
Site name: ゆれぬこましーん (Nurenuko Machine)
(He has some private accounts, too. They're not related to danbooru though.)
https://www.pixiv.net/users/3279051
https://www.pixiv.net/stacc/kuuichi09
https://seiga.nicovideo.jp/user/illust/9328879
http://com.nicovideo.jp/community/co1622133
https://www.nicovideo.jp/user/9328879
https://nijie.info/members.php?id=2697
https://pawoo.net/@kuuichi09
https://kuuichi09.fanbox.cc
https://sketch.pixiv.net/@kuuichi09
https://www.tinami.com/creator/profile/14397
https://kuuichi09.tumblr.com
https://ask.fm/kuuichi09
http://c10270581.circle.ms/oc/CircleProfile.aspx
http://c10270582.circle.ms/oc/CircleProfile.aspx
http://danbooru.donmai.us/users/444626
https://www.pixiv.net/users/1487804
https://www.pixiv.net/stacc/kuuichi
https://twitter.com/kuuichi09
http://twitpic.com/photos/kuuichi09