The Soul of Rebirth is a bonus quest in the Dawn of Souls, 20th Anniversary, and iOS versions of Final Fantasy II. It becomes available after defeating The Emperor and completing the game. The player can then select "Soul of Rebirth" from the menu.
Minwu awakens in a new area following his sacrifice to unseal the door guarding the Ultima tome. He overhears a battle and sees someone resembling Gordon fighting off some Imperial soldiers. Minwu assists him and the man explains afterwards he is Scott, Gordon's brother. Minwu informs him of the pivotal role in the resistance that Firion, Maria and Guy have become, and the two surmise they are in the Jade Passage, the pathway to Hell, since they are both dead. Continuing onwards they find Josef fighting Zombie Borghen, and assist him in dispatching the count once again. The three find a Roundworm and approach it when Ricard appears and helps them fight it, saying it followed him to Hell when he killed it before.
The four finally emerge from the cave in Machanon, a village in the mirror image of Poft where the citizens are dead victims of the Emperor's conquest, including Cid and Tobul. The people tell the group they appeared in this mysterious realm full of monsters without reason and have lost many of their number to these monsters, fleeing and building this makeshift town when they found a safe area. Additionally, a mysterious teleporter at the north edge of town has appeared since the four arrived, and the village takes hope in them fighting off the monsters. Another portal leads to a chamber resembling the Ultima chamber, where Minwu discovers another copy of the Ultima spell, but the Ultima Weapon must be killed to claim it. Cid tells the group that though the region is full of deadly monsters, he doesn't believe it to be Hell, as if it was it is unlikely innocent children would have appeared here. Cid asks Minwu and the group to find out where they all are and why they have been called here.
The four enter the teleporter at the north edge of town and enter what Minwu says is Pandaemonium, palace of Hell, and climb to the highest floor where they find the Emperor on the palace's throne. However, Ricard notes this Emperor is different from the one he faced. The Emperor explains that when Firion and his allies killed him, his soul was split into two. The Emperor's "dark half" fell to Hell and acquired more power, while his light half - the Emperor they now see - ascended to Heaven. The Emperor explains that though the two look alike, they now stand in Arubboth, palace of Heaven, and the cave they traveled through was actually Raqia, the place where fallen angels are cast down to become demons. The Emperor explains he called them all here to ask for forgiveness on the behalf of his dark half, and offers them eternal life with him in Arubboth if they agree to forgive his sins.
Though the four are tempted with his offer, apparitions of their loved ones appear and show them a vision of Firion and his allies battling the Dark Emperor in Pandaemonium. Realizing this Light Emperor is just as evil as the original, the four reject his offer and engage him. Defeated in battle, the Light Emperor declares their history of war and violence will continue, then dies just as Firion and his allies vanquish the Dark Emperor. As the rebels in the world of the living celebrate their victory, the specters of Minwu, Scott, Josef and Ricard watch them and wish them well. When their former allies leave, the four turn to each other and agree that their time is up, and they fade away into peaceful rest. Minwu comments that if anyone can change man's legacy of violence, it is Firion and his friends.
Soul of Rebirth gives the player a party consisting of three party members they had in the past, with the addition of Scott. Except for Scott, those three join the party with whatever spells, equipment and stats they had when they left the party, so the player is advised to plan for this ahead of time during the main game if they plan to play Soul of Rebirth - in particular, the player may wish to teach Ricard Ultima or equip him with the Blood Sword in the main game, as he will carry these skills over to Soul of Rebirth where they can be quite effective. The vast differences in stats between the party also means the player will likely have to do a lot of level grinding to build up their stats enough to complete the quest. The shops in Machanon sell higher level equipment than what the party likely has initially, and many monsters in Arubboth drop rare and powerful armor. In addition, an "ultimate" weapon can be found in chests for each of the four party members.