Sadly, it appears the artist has deleted this work from their pixiv, since this was either card art for an official card (in which case, copyright might've become a concern) or was drawn for the Ange Vierge Illustration Contest (the Ange IlluCon, or アンジュイラコン on pixiv), in which case they probably just deleted it when it didn't win/the IlluCon became moot when AV shut down in early 2018. With the shutdown of the game, this is likely the final archived version of the art online.