Firion begins his storyline with Tidus as they search for their Crystals. Firion is lacking his wild rose, having had it stolen by Sephiroth earlier. Tidus asks Firion what his dream is, but Firion has no answer, wishing only to end the war. They continue on and decided to split up when the manikins grow in number. At the Lunar Subterrane, Firion meets Jecht, having been dismissed by the Emperor when the latter confronted Tidus. Irritated by the Emperor, Jecht attacks Firion to vent, but Firion eventually refuses to continue fighting, telling Jecht his true enemy is his son. Jecht leaves to meet with the Emperor while Tidus arrives, Firion realizing father and son are very much alike.
In a scene showed in full in Tidus' story, Firion and Tidus find the Emperor and Jecht arguing, and the two attack each other. The Emperor teleports while a weakened Jecht limps away, Tidus refusing to fight him in his condition. Tidus tells Firion he's going to pursue Jecht, and Firion gives him a potion he's been saving. After Tidus leaves the Emperor reappears and taunts Firion with his lack of a desire, while his companions have left him to pursue theirs. When Firion reiterates his dream is to end the war, Ultimecia appears and does battle with him. Firion wins but the sorceress reappears unharmed, and she and the Emperor tell Firion he only fights because Cosmos tells him to, and as a mere mortal he cannot end a war fought between gods.
Firion continues on to pursue clues that could lead him to the Land of Discord, when Cosmos appears to him to inform him his friends have claimed their Crystals. Firion is happy for them but is troubled by the Emperor's words, and tells Cosmos unlike his friends he has no goal to chase. Cosmos assures him he does have a dream, and asks him to describe it to her. Firion tells her he dreams of a world where wild roses can bloom freely, a metaphor for a world free from war and death. Cosmos says that this dream is Firion's, not hers, and his desire to see it fulfilled means he is no tool. Encouraged Firion continues into the next gateway to find the Emperor waiting for him, who taunts him and incapacitates him. Tidus and Cloud arrive to protect him and the Emperor teleports away, telling Firion to follow him and prove his power. Cloud gives Firion back the wild rose Sephiroth stole from him, telling him his friends too wish to see his dream come true.
Firion journeys beyond the gateway to find a teleport stone to the Land of Discord, and enters a gateway nearby to confront the Emperor. In Pandaemonium, Firion finds the Emperor, who tells him he will erase Firion's dream. The Emperor temporarily incapacitates him, but Firion rises back up and continues the battle, ultimately defeating him. The Emperor fades into darkness, warning Firion that his dream will crumble and he will beg for the Emperor's rule. Firion claims his Crystal and thinks that the battle has just begun, but he will continue to dream and fight until his world of wild roses becomes a reality.
A Multichain at B3 or a Jump Chain at C3 will chain the four enemies present, the latter option allowing usage of the Booster x5 emblem. Enemies in Firion's story use accessories that greatly boost their damage output while they're in EX Mode, and enter battle with a full EX Gauge.
A Multichain at C3 will chain the four enemies here. The player can find a KP Gambler on the world map, but the player should consider saving it for the Encounters and Treason gateway later in the story, as there the five-enemy chain will yield 75 KP, while using the KP Gambler here will only award 48 KP. Be wary of the Strange Battle Piece, as it has the PuPu summon to constantly boost its Bravery, making Breaking it to earn KP difficult. Jecht is fought as the boss of the stage.
A Multichain at the starting point or a Jump Chain at either C3 or D2 will chain four of the enemies, the latter two options allowing the player to use either of the purple Emblems. There is no way to chain all five enemies as once, however.
Assist Character - Tidus
Tidus: I'm backing you up, so keep up the offensive!
A Multichain at D4 can chain all five enemies, the most the player can chain in Firion's story and thus the perfect chance to use the KP Gambler found earlier. Ultimecia is fought as the boss of this stage. Tidus is unavailable as an Assist in the fight.
Tidus: I'm fine! Don't go worrying about me. I'm just focused on fighting now.