You might be wondering what changes from canon have occurred on the MUSH. This newsfile will answer most of those questions!
Final Fantasy 1
The events of FF1 are basically as happened. Even Elfland being there and suddenly disappearing. Garland knocked people down, then Garland was knocked down. What happened after that is not certain to the general populace.
The Warrior of Light is the main character of the game, as characterised by Dissidia as a nameless individual with no memory of who he was before he became Warrior.
Red Mage of Light is Aria Bennet from FF3, who has been aged and transformed into the first Onion Knight.
Black Mage of Light is Sage Tellah from FF4. The events of FF1 are before he became a Sage.
Monk of Light is Duncan Harcourt from FF6. After FF1 he retires like in 6 and is "killed" by his son Vargas.
Final Fantasy 2
Events occur broadly as they do in the game. Small differences are present such as the events of when Firion and co escape Fynn, how they come across Prince Scott.
The Wild Rose is a magical artifact similar to as seen in Dissidia that is in Firion's possession.
Final Fantasy 3
The Floating Continent exists, but cannot be found due to powerful magical illusions. The Churches maintain that it is a heretical remnant of the people who lived in the magic war, unlike the Sky Continent of Dorstonis.
Names from the DS version are considered canon.
The Onion Knights came into contact with crystals on the floating continent and were then transported to the surface, where they became involved with the Heretics.
The plot of Final Fantasy 3 is largely incompatible with the MUSH and has been largely changed. Minor events and adventures are supposed to have happened, characters who joined them were transported down to the ground.
Alus Restor and Aria Bennet have been aged and their stories altered.
Luneth is a cross between his DS incarnation and his Dissidia one, and he inherits the title of Onion Knight from Aria Bennet.
Final Fantasy 4
Tellah is a Light Warrior. After his journeys saving the world he retired, came out of retirement to help form the Heretics.
The Kingdom of Baron is an ally of the Empire.
Fabul is located near Spira and follows the Yevon religion. They have their own temple and Fayth, Kirin.
Eblan has been destroyed by a combination assault by the Empire and Rubicante, the Fiend of Fire. Eblan was also a Yevon-influenced country, and its Fayth, Phoenix, remains intact.
The Crystal of Water has already been taken from Mysidia, and Mist has been destroyed.
Toroia possesses the Crystal of Earth.
Final Fantasy 5
As of the start of the game, none of the crystals have shattered yet. But the party members have been brought together and joined the Rebellion.
Karnak has the Crystal of Fire.
Tycoon has the Crystal of Wind.
Final Fantasy 6
Doma is located near Spira and follows the Yevon religion. They have their own temple and Fayth: Asura. Doma is a massive citadel-fortress that could easily withstand even a Magitek-equipped army.
The Magitek Knight process has been altered to allow for multiple OCs.
Final Fantasy 7
FF7 is generally beginning in the Before Crisis/Crisis Core era.
The Shinra Trading Company is now a powerful merchant house, using steampunk technology and innovative magitek in order to extend their financial dominance. They are heavily allied with the Empire through the nearby Vector and Baron.
Firion and his group attempted to prevent the Corel Incident from getting out of hand, but the original AVALANCHE organization moved to attack anyway. The nascent Rebellion's actions there saved a good number of lives... Though it did not save the city.
The Wutai War has not occurred yet, but likely will soon. Yuffie has been aged to compensate and to allow people to play her as only being mostly a spaz.
Shinra's base of operations is the Machine City Goug, situated in resource-rich foothills.
SOLDIER has been used in several military conflicts, including ending the Fifty-Year War. Sephiroth gained fame as being the strongest man in the world by besting the leaders of the Nanten and Hokuten armies and bringing them to the bargaining table.
Tifa became involved with AVALANCHE after the Empire destroyed Nibelheim in an attempt to purge a Wild Rose Rebellion cell. Shinra rebuilt Nibelheim and installed a Mako Reactor, but it instilled an anger against Shinra in Tifa.
Shinra is heavily involved with the Empire, profiting off of their activities and supplying them with materials for war.
Wutai has a major Yevonite presence, even possessing their own Fayth, Leviathan.
The events of Before Crisis happened broadly as they did in the game. FF7 is rougly set approximately around the beginning of Crisis Core.
Final Fantasy 8
Trabia Garden is now Toroia Garden. This might explain Selphie. Trabia itself is considered a small portion of Toroia.
Esthar has been downleveled from superfuturistic and modern technology to merely advanced on the general level of Archades, with their own unique twists.
Galbadia does not have ICBMs.
Gunblades are considered to be brand new technology. Hence the design flaws.
Final Fantasy 9
The Iifa Tree is now located in the center of the Feywood, and is (one of) the source(s) of a massive amount of Mist being exuded through the entire region.
Final Fantasy 10
Wutai, Doma, Fabul, and Eblan all have the Yevonite religion present, and each location has their own Fayth: Wutai has Leviathan, Doma has Asura, Fabul has Kirin, Eblan has Phoenix.
Yuna's pilgrimage has been altered as a result, and joined the Heretics after viewing the message from Seymour’s father’s Sphere on Thunder Plains.
Final Fantasy 12
Events occur broadly as they do in game.
Final Fantasy Tactics
The Kingdom of Ordalia is renamed to Rozaria to differentiate it from the continent.
The Kingdom of Ivalice is renamed to St. Ivalice to differentiate it from the world.
Otherwise, events occur broadly as they do in game.