The two characters on the right are the main characters in aki_poi's serialised work Rokujou no Hitoma no Majo Life, or A Witch's Life in a Six-Tatami Room. Can't tell the character on the right, but might be Miyazen from his other series Ochikazuki ni Naritai Miyazen-san, which already has the web version uploaded and translated here, but also has a serialised version.
Edit: I saw the pixiv upload, and yes it is Miyazen. Tagging all characters.