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 iOS, PSP and PC versions, the letters unlock at certain points over the course 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.
Players use Mognet by speaking to moogles found in nearly every town in the game. In the Nintendo DS version, players may exchange letters with each other through wireless communication. This can be done remotely with two handhelds next to each other, or through Nintendo WiFi Connection by exchanging friend codes. Up to 28 friend codes may 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 all the letters players 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 NPCs' lives after they met the Warriors of the Light, or offer commentary on the plot. Letters may only be sent once per hour.
To receive letters after the first one in the Nintendo DS version, the player must send seven total letters to other players through WiFi. These can either be sent to multiple players or all to the same person. Since the iOS release lacks 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.
Players can send mail to Topapa when Mognet first becomes available after defeating the Djinn in the Sealed Cave. In the iOS version, Luneth must be at the party leader to receive any letters after the first. After receiving the fourth letter, the player may begin the Onion Knight sidequest.
Players can send mail to Takka any time after Refia rejoins the party on Cid's airship when departing for Canaan. In the iOS version, Refia must be at the party leader to receive any letters after the first. To receive his fifth letter in any version, the player must have first reached Eureka. Receiving all five letters is a requirement for the Ultima Weapon sidequest.
Players can send mail to Sara Altney any time after returning to Sasune after defeating the Djinn in the Sealed Cave. In the iOS version, Ingus must be at the party leader to receive any letters after the first, and in both versions he must be at the front to receive the fourth. Receiving all four letters is a requirement for the Ultima Weapon sidequest.
Players 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.
Players 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 all treasures in the Sunken Cave have been obtained. All four letters are required for the ??? dungeon sidequest.
Players can send mail to Alus Restor any time after defeating Garuda in Saronia. In the iOS version, Arc must be at the party leader to receive any letters 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 obtained, 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 obtained, 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.