Fairly sure this is original, just wanting a more accurate translation on the commentary to make sure (since it isn't tagged as such on nijie).

Commentary: 前にも描いた某フリゲのキャラです
Tag?: ノエル

She's apparently a character in some F2P RPG (don't know exactly which with just the commentary.) I would assume the tag to be her name, Noel.

She is ノエル・ウィンターグリーン (Noel Wintergreen) from Abare-Usagi's free game, メイデンスノウの妖怪大魔境 (Maidensnow no Youkai Dai-Makyou/Daimakyou).

• Official page: http://maidensnow.web.fc2.com/games/special_daimakyo.html
• Fanmade Wiki: http://www16.atwiki.jp/maidensnow/