http://www.mangago.zone/read-manga/k_sensei_no_himitsu_no_netsujou/uu/k_sensei_no_himitsu_no_netsujou-chapter-3
It's a Fate/Zero fanart I think. Sorry, nobody replied you and I had to guess.
http://www.mangago.zone/read-manga/k_sensei_no_himitsu_no_netsujou/uu/k_sensei_no_himitsu_no_netsujou-chapter-3