Artist.
Japanese name: 田中 いお (Tanaka Io)
The other names: 伊於 (Io), 芙蕗 伊於 (Fubuki Io) or "io0302"
Circle name: クラフトスタジオ (craftstudio)
Site names: "-ion" or "暇乞い.com"
(She has some real person fiction-themed accounts, too. They are not related to danbooru though.)