Artist, illustrator.
Japanese name: 優鬱 (Youutu) (reading is a best guess)
https://www.pixiv.net/users/448630
https://www.pixiv.net/stacc/fate2663
https://twitter.com/youtoo01
https://twitter.com/intent/user?user_id=102287223
https://seiga.nicovideo.jp/user/illust/4490303
https://www.nicovideo.jp/user/4490303
https://sketch.pixiv.net/@fate2663
https://www.tinami.com/creator/profile/8266
https://www.stickam.jp/profile/youutu
http://twitpic.com/photos/youtoo01