Im pretty sure I found the sauce!

• SauceNao SourceURL:https://www.pixiv.net/member_illust.php?mode=medium&illust_id=79811186
• Title:「二月２０２０年」リクエスト＃7
• PixivId:79811186
• MemberName:DjayO
• MemberId:1964140
• Similarity:91.95

Found On Trace.Moe with a similarity of 0.91: - Title English:Dragon Rider

• Title Romaji:Dragon Rider
• Title Native:Dragon Rider
• anilist Id:3551