A student at Rigarden and Will's roommate who professed to have been in love with him and had a slightly androgynous appearance. Unlike others, Rosti didn't look down on Will before his win over Julius during the Great Magic Festival. Rosti is a skilled magical artificer and makes magic items for Will to use. Despite not having any innate talent for magic item making, he is a genius that has created various magic items for Will's sake.