I've personally called him Janus for the better part of two years, forgoing that blasted title Magus. I'm too well aware of it being a title, rather than a name and, in fact, once called him Janus Magus, ie. Janus the Sorcerer. I don't know if anyone's noticed, but often I'll just call him the Sorcerer, which is essentially like calling him Magus, only in English translation. If one really wants to be picky, though, call him Magos (Μαγος), as that is the older spelling of it. I don't, however, think it is a general title. He is THE Sorcerer, not just the lord sorcerer. That would be Anax Magos, or Basileus Magos (or something like that, I'm guessing, and I don't know the declensions for different cases), or maybe yet Domino Magus, or Rex Magus. Anyway, I usually call him Janus (Yah-nuss), save in his position as the sorcerer of the Mystics. There he is Magus (Mah-gus).