Grezzo is the late father of the standing head of the Tenshodo, Aldo, and probably that of Aldo's sisters Verena and Mathilde although this has not been specifically stated. Grezzo held a similar standing during his lifetime to that of his son in the present, possessing some high degree of rank within the Tenshodo. He was known of by Prishe from the time before the Great War when the Tavnazian Archipelago was still in communication with the mainland and he had assured Prishe of the assistance of the Tenshodo if she were ever to need it.