This seems to be Shittori Oblate. I just saw the KanaMari picture on their pixiv.

http://touch.pixiv.net/member_illust.php?mode=medium&illust_id=57955665

e: or maybe this is just one artist of the circle. Don't nail me on it.

last edited at Aug 4, 2016 11:38AM

^Yeah, I came here from their recent releases and thought I recognized that art somewhere.

Love this artist's art and style of storytelling!!