The Age of Ash
This Dragonborn professor of history was a close associate of Master Tong’s. He organized the first expedition with the help of Tong’s funding, and led it to the library. Clues that Balthazar left behind on the first floor of the Library’s main tower helped the party unlock the door to the Vault.
A page torn from his notebook indicates that Balthazar left the library in a search of “the missing Observatory.”