I doubt this is AI. The sketch was posted here. And despite the artist stating they were not in the mood and only drawing sketches at that moment, most on that link have been completed and some even uploaded (e.g. post #6250773). However, can't find the original tweet, as he's deleted everything related to Rakkun and Owozu, such as post #8256600, which even I remember it being posted by Slash-Ex on Twitter but cant find anything.