| This article is based on data from a Japanese-only game.|
The following content has not been released in the English language, so details are subject to change at any given time.
|Game||Tales of Phantasia: Narikiri Dungeon (X)|
When Norn sends Dio and Mell into the cloud painting, they are tested in combat by Flambelk, Fen Beast, Big Eye, Justona, Ishrantu, and finally, Dhaos, to learn the truth about their past. There, they learn that they were citizens of the country Palace Gudora on the planet Derris-Kharlan. The country was at war with another small country, Palace Sedamyu. When he was 27, Dios was a soldier in the country's military. In this revelation of the past, Dios reports to his adoptive father, General Bandi, that their country is losing and delivers a message from Dhaos, the prince of the world's largest country, warning them to stop the war because of all the innocent people dying. However, the general insists on ignoring the message, and when Dios reminds him of the great power Dhaos's country has, the general forces Dios's obedience by reminding him that he would have died had the general not adopted him, stating he has a duty to give his life for his country.
As Dios predicted, the enemy country defeats Palace Gudora with a massive attack that results in the loss of approximately 80 percent of its population, as well as the majority of its military forces. Before dying, the general orders Dios to fire the Mana Cannon that his adoptive sister, Meltia Bandi, had been preparing. General Bandi makes it evident to Dios that their country has no future now that they have lost, leaving his final order to resonate with Dios as his superior officer and father. When Dios makes it to where Meltia had been working on the Mana Cannon, he finds her covered in blood. She is gravely wounded and dies shortly afterward. Believing his country to be doomed, Dios realizes the systems of the Mana Cannon are still functional, so he fires it. The blast immediately kills around 150,000 people, as well as the Giant Kharlan Tree, which provided the planet with mana. Dios, feeling the mana fading from his body, then dies himself.
Some of these events were changed in Narikiri Dungeon X. In this game, General Bandi adopted Dios after his parents were killed, as opposed to adopting him as a baby. In the general's final plea, he reminds Dios of what happened to his parents, further prompting him to act. Also, Meltia is not injured when Dios makes it to the cannon, and she informs him that the cannon will be safe to fire in three days. However, Dios believes there is no time and fires it anyway, resulting in the deaths of 150,000 and the Giant Kharlan Tree, as well as his and Meltia's when the planet's mana begins to fade. In both versions of the game, Norn appears to the two after their deaths and tells them that they must be punished for their actions. She informs them that she will reincarnate them in another time and place in order to determine whether they are good or evil. However, if they gave her any indication of repeating their previous mistakes, she would kill them for good. Dios and Meltia are then sent to Aselia in the year 4395 AC as infants and renamed Dio and Mell, respectively.
When Dio and Mell encounter their alternate selves, they witness scenes of the Heroes of Eternity suffering with their problems while their alternate selves comment. Claus F. Lester is worried about becoming too much like his father, whom he hated for being too involved in research to spend time with family, and Milard Rune comforts him. Dios notes the similarities between love and hate but asks who those without parents are supposed to emulate. Arche Klein, who has a long lifespan, misses all her human friends, especially Chester Burklight, and Dios says that separation is too painful, so one may as well never become attached to someone anyway.
Cress Albane is giving his support to Mint Adenade, who is recovering from illness, and Dios criticizes her because she is needed by many people and does not understand what it means to be unloved. Afterward, Dio and Mell fight Dios and Meltia, who remind them that this violates the principles of cause and effect and creates a paradox because they have killed their past selves. However, after the fight, they become one with their dark sides again. Finally, Couleur walks out in front of them and reveals that it has been Norn the whole time. As their final test, Dio and Mell must defeat Norn in battle. After they win, Norn says that the flow of time will correct them. They are once again reborn, and their adoptive parent, the player, finds them as babies again.