Almost certainly, though I don't know what story you're talking about specifically. Circe and Mina (gothy witch and forest demon) are two of Steve's OCdonutsteels. He's a mainstay at animeotk.com and one of the better artists on the site. Most of the stuff there is pretty deviantart-tier, but membership is free so it's cool.
This piece was commissioned by another fetish artist called Congolike who used to post a lot on animeotk before moving to the furry community. He has a tumblr called diamonddogs (or something to that effect) about, of all things, mlp s/m art.