Les trois vœux (слэш)

De Sardet goes looking for a book about a Congregation folk tale and what he finds is an old book of magic instead. He's always wondered what it might be like to be without his strange green birthmark, and so he casts a spell to change his face and goes out into the town to test his work.
He doesn't mean to meet Constantin. He doesn't mean to deceive Constantin. But despite his best intentions, that's what happens - when his cousin asks him for his name, he calls himself des Vœux. When his cousin asks him to join him in his room, he knows what he means but still does exactly that.