The game will unite both protagonists and antagonists from installments of the main Final Fantasy series. Chaos will also make an appearance as the god of darkness, while a new character, Cosmos, will appear as the goddess of light. It is unknown, however, if these two will be playable or not. Recent articles released in Japanese magazines have stated that the game will have a storyline that requires playing through all of the characters to complete. There will be a minimum of twenty playable characters, and hidden characters are a possibility. Characters can gain customizable equipment, and will also be able to earn experience, gain levels and gil. Characters will have alternate costumes, including Squall's SeeD uniform, Firion's red caped costume from one of his Amano designs, and a design change for the Onion Knight that makes him resemble Luneth from Final Fantasy III DS.
Some of the characters are confirmed to have different forms in their EX modes, as well. Warrior of Light from Final Fantasy can transform into his upgraded class form (as bestowed by Bahamut in the game). Onion Knight from Final Fantasy III can transform into a Ninja or a Sage, the most powerful job classes from the NES version of the game, and Cloud of Darkness appears in her original green form with her two serpent minions. Additionally, Cecil from Final Fantasy IV switches between his Paladin and Dark Knight jobs. Golbez can fuse with his Shadow Dragon, the latter also seen in Final Fantasy IV. Exdeath can transform into his tree form, as seen in Final Fantasy V, and utilize the powers of the Void. Terra from Final Fantasy VI can morph into her Esper form. Ultimecia from Final Fantasy VIII can fuse with her Guardian Force, Griever. Zidane and Kuja from Final Fantasy IX are shown in their Trance forms, while Jecht from Final Fantasy X transforms into Braska's Final Aeon.
Summons have also been confirmed to appear in the game and they will be accessible using Summon Stones. There will be over 50 types of summon in the game and they will all do completely unique things to affect a battle. So far Ifrit and Carbuncle have been revealed on the Japanese website of Dissidia.