After reverse google search:
Author's Instagram page (Russian) : https://www.instagram.com/potishah/
Both pictures of his work in place and the picture of it being stolen are available.

reverse google search shows that this is an in-game screenshot from a gay dating sim called 'coming out on top'.
Steam game page:
http://store.steampowered.com/app/642090/Coming_Out_on_Top/
Developer page:
https://obscurasoft.com/

After a ton of reverse google search:
Full Res: https://danbooru.donmai.us/data/__rixia_mao_ao_no_kiseki_eiyuu_densetsu_sen_no_kiseki_sen_no_kiseki_2_and_zero_no_kiseki_drawn_by_kakekcaboel__e7962d4fc9633065e932991197005f53.jpg
Seem to be fanart for a character Rixia Mao from the 'sen no kiseki' (The Legend of Heroes) series. And the games in which she appeared in are :Zero no Kiseki, Ao no Kiseki and Trails of Cold Steel II.
Author seems to be someone with the name 'kakekcaboel' or 'kakeku' which is likely the new name, page: http://kakeku.deviantart.com/

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