When the party first meets Mogryo in the Black Mage Village, he will have a letter: He sends a letter to Mocchi at the Iifa Tree: After the party has returned from Terra they can start a side quest to fix Mognet Central by talking to Kupo in Alexandria. As part of this chain of letters Atla in Burmecia sends a letter to Mogryo: Mogryo in response sends a letter to Kumoon in Ipsen's Castle: