Circle composed two artists: Howaito (ほわいと) and Sacchin (さっちん). Their joint pen-name is アラワタ (Arawata).
https://www.pixiv.net/users/1955453
https://www.pixiv.net/stacc/arawata-country
https://twitter.com/Alexandra4rwt
https://twitter.com/intent/user?user_id=4874275740
https://nijie.info/members.php?id=3961
https://sketch.pixiv.net/@arawata-country
http://a4rwt.blog.fc2.com
https://twitter.com/meatpatty_kun
http://theinterviews.jp/arawata930
http://twitpic.com/photos/meatpatty_kun