Mognet(モグネット, Mogunetto?) is a feature which first appeared in the Nintendo DS remake of Final Fantasy III. Unlike Mognet in Final Fantasy IX, this service is not for moogles, but for the player. Before the shutdown of the Nintendo Wi-Fi Connection service for Nintendo DS on May 20 2014, people had the possibility to trade friend codes and send letters via the Wi-Fi network. Unfortunately, this means that current DS players can no longer utilize the Mognet service to its fullest, and new players will only be able to use local DS-to-DS wireless communication to access the extra features it unlocks.
Mognet works a little bit differently for the mobile, PSP and PC versions, where the letters unlock at certain points of the story. The player will have to read the new piece of mail at a moogle found in towns before getting the next mail.
The player uses Mognet by speaking to moogles found in nearly every town. In the Nintendo DS version, the player may exchange letters with each other through wireless communication. This can be done remotely with two handhelds next to each other, and before the service was shut down it was possible through Nintendo WiFi Connection by exchanging friend codes. Up to 28 friend codes could be stored at a time in the address book. Letters may be up to 125 characters long using no more than five lines (25 characters per line).
Below is a list of the letters the player can receive from non-player characters. The ability to send mail to each character is unlocked at different points in the story. Whenever a player sends a letter they will instantly receive one back, which often reveals details of the recipient's life after they met the Warriors of the Light, or offer commentary on the plot. Letters may be sent once per hour.
To receive letters after the first one in the Nintendo DS version, the player must send seven letters to other players (either to multiple players or all to the same person). Since the mobile, PSP and PC releases lack the ability to send mail to other players, these letters are unlocked automatically after the player has obtained the Fire Crystal from the Molten Cave, though some require a specific character to be at the lead in the party to receive them.
The player can send mail to Topapa when Mognet first becomes available after defeating the Djinn in the Sealed Cave. In the mobile, PSP and PC versions, Luneth must be the party leader to receive any letter after the first. After receiving the fourth letter, the player may begin the Onion Knight sidequest.
The player can send mail to Takka any time after Refia rejoins the party on Cid's airship when departing for Canaan. In the mobile, PSP and PC versions, Refia must be the party leader to receive any letter after the first. To receive his fifth letter in any version, the player must have reached Eureka. Receiving all five letters is a requirement for the Ultima Weapon sidequest.
The player can send mail to Sara Altney any time after returning to Sasune after defeating the Djinn in the Sealed Cave. In the mobile, PSP and PC versions, Ingus must be the party leader to receive any letter after the first, and in both versions he must lead to receive the fourth. Receiving all four letters is a requirement for the Ultima Weapon sidequest.
The player can send mail to Cid Haze any time after they have dropped him off at his home in Canaan. The fourth letter cannot be received until the player has met the Legendary Smith. Receiving all four letters is a requirement for the Ultima Weapon sidequest.
The player can send mail to the Four Old Men any time after they obtain the Levigrass Shoes from Delilah in the Amur sewers, defeat Bahamut, Leviathan, and Odin, and after collecting all treasures in the Sunken Cave. All four letters are required for the ??? dungeon sidequest.
The player can send mail to Alus Restor any time after defeating Garuda in Saronia. In the mobile, PSP and PC versions, Arc must be the party leader to receive any letter after the first, and to receive his fourth letter, the player must first obtain a job's Master Item by reaching job level 99 on one character, and speaking with the Legendary Smith. All four letters are required for the ??? dungeon sidequest.
The player must send and receive four letters from Topapa. After the fourth letter is received, the player must travel to Ur and speak with him, and then to the Altar Cave where they must save some children from three Bombs. After the battle, the player is rewarded with a crystal fragment which unlocks the Onion Knight job.
The Ultima Weapon quest is divided into multiple parts. First, the player must send four letters to Princess Sara, where she asks for help in repairing her mother's pendant. The player must send and receive five letters from Takka, and once the fifth letter is received, he will tell the player about the Legendary Smith who can be found in northwest Saronia.
When the player sends and receives four letters from Cid, they will be tasked with slaying a monster in his basement and are rewarded with a piece of Orichalcum. By finding the Legendary Smith in Falgabard after opening the door to Eureka and giving her the Orichalcum, she will forge the Ultima Weapon from it.