Urianger is the master of riddles, even the writers are confused about him. I suspect they're trying to keep MSQ not to sound as vague as a sightseeing log, but he will jump-in out of nowhere like he always do anyway. Shame he has to be 'unavailable' this time but there's also the less-known Scions like Harry Boulder or Ephemie. I think they will take his spot this time because I can imagine Alisae staring blankly at Urianger's words.