19. "The path of the angel's descent."
From Quiz "LastEXILE" - What Lies Beyond The Sky
Answer:
The Grand Stream
"The path of the angel's descent."
"Thou art the path of the great winds - The Grand Stream."
This is the Bashianus Mysterium, and Alex was sure never to learn it, in case he was captured by Maestro Delphine (and he was, too). This Mysterium was posessed by Marius Bashianus, the prime minister of Anatore, and the last surviving member of the Bashianus Family. The Mysterium was sent to Alex in writing by carrier pigeon, and he passed it on to Sophia without reading it. Claus says this to Alvis in the final episode.