- For the previous holder of the Aeona title, see Aeona the 1st.
While both sisters had the powers of a Transcendent, only one could have the title, and the name of Aeona. The purple haired sister was given the power of darkness and death, while Tana had the power of light and creation. The purple haired sister was picked as the Transcendent as she could hear a 'voice' and given the name of Aeona, and the black haired sister was left to be just a 'half', naming her "Tana". Soon, Aeona goes mad with power and Tana supposedly kills her sister, takes her power and thus her name, as a result. Now shackled by the very same 'voice' her sister heard, Tana refuses the Aeona name and leaves Grandis, abandoning her duties as Transcendent. She soon finds her way to Kritias, where she gets involved in a disaster that sends Kritias to the future. She would later be absorbed by the Black Mage against her will.
The player encounters Arkarium once again in Morass, attempting to trick Tana into helping the Black Mage. Tana, having lost her memories and possessing power beyond what is known, turns the entirety of the Morass into a replica of Kritias, before it was struck by disaster. As a result, the player and the Flying Fish are also affected, being turned into Shey, a traveling priest, and Jean, a local boy, respectively, and are forced to relive the memory of Tana.
In the 52nd year of the Hekatonian calendar, a tragedy struck Trueffet Square in Kritias; a rope supporting an Anti-magic Stone snapped, causing the stone to fall and explode, killing everyone in the vicinity except for one girl: Tana, whose body regenerated in front of everyone, but causing her to lose her memories. She was then captured by the guards and taken to the dungeon of Trueffet, where she was experimented on to find the source of her immortality and transfer it to King Hekaton. Having experimented on her for nearly 2 years, the researchers discover that while her body regenerates itself perfectly, her memories and emotions were always erased, leaving Tana as a blank slate. Due to the nature of the experiments being both inhumane and beyond their understanding, the former High Priest resigned, stating that "This is neither magic nor science. It is beyond human; it is of the gods. We have overstepped our bounds."
Even though the High Priest resigned, a new High Priest agreed to help with Hekaton's mission, Arkarium (who was still serving the Goddess Rhinne at the time). Arkarium made great progress, but Tana was rejecting the transfer of power to many test recipients (leading to their bodies disintegrating, but their souls remaining, desperately attempting to recreate new bodies). During another experiment, King Hekaton appeared, demanding the researchers increase the power of their experiments beyond the limit. A massive explosion occurred as a result, but Hekaton was unharmed (aside from a strange aura surrounding his body, indicating a loss of humanity).
Jean breaks into the dungeon to visit Tana repeatedly, comforting her and reading stories to her, including a story about a knight rescuing a princess, which he relates to their current situation (Jean wanting to be Tana's metaphorical knight). One day, Tana reacts and is about to explode, but Jean manages to calm her down by hugging her, ending the reaction, and leading Arkarium, who witnessed this unbeknownst to Jean, to realize that Jean is the key to ensuring a successful transfer of power to King Hekaton, due to Tana having feelings for Jean. Jean formulates a plan to escape with Tana, and asks for Shey to help him find an Anti-magic Stone Necklace as a wedding gift for Tana. Jean and Shey then encounter Arkarium, who tricks the two into thinking he wants to help Tana escape to prevent a horrible disaster from engulfing Kritias, as well as causing Tana endless pain.
On the day of Jean's plan, Shey (who regains consciousness as the player) realizes that Arkarium, who was never truly under the influence of the Morass, led the two of them into a trap, and Arkarium calls for the guards (which he originally brainwashed the real Shey to do), who then proceed to kill Jean, leading to the ritual succeeding, and transferring power to King Hekaton. However, Jean had a backup plan: the necklace he gave to Tana contained unstable magic, which she took advantage of by destroying mid-ritual, leading to her body disappearing and Hekaton being cursed eternally.
Arkarium then kidnaps Tana and attempts to transfer her power to himself. The player goes to take down Arkarium after realizing that Jean, who was really the Flying Fish, is still alive. After the player fails to defeat Arkarium, Jean appears to console Tana once more, ending the ritual. Tana, who has now gained control of her powers, defeats Arkarium.
In the aftermath, the player, who has now regained full consciousness, talks to the Flying Fish, who is still stuck in the form of Jean due to Tana having a stronger influence on Erda. Jean tells the player that Tana may side with the Black Mage now, as the only way to end Tana's pain is to destroy the world. As they speak, Tana briefly considers destroying the player, but decides against it when she sees the Flying Fish, in the form of Jean.
The Alliance encounters Tana sealed inside a glass coffin by Will, who is preparing to conduct a ritual that will transform Tana into the white sun. Orchid, in disguise, interrupts the ritual, causing Tana to fall into the seas of Esfera. Her powers interfere with Will's, causing her memories to seep into the Mirror World. As the Alliance attempts to rescue her from the bottom of the sea, they learn the truth about Tana's origins: She is the twin sister of the previous Aeona.
Long ago, while the Executors of Light and Dark were deciding on the transcendent of light, the purple haired sister demonstrated that she could hear a 'voice', so they made the purple haired sister the transcendent and named the black haired one 'Tana'. Aeona had the powers of darkness and death and Tana had the powers of light and creation.
At some point, Tana was reading a book to the reasoning of why they can only control one power. She finishes the sentence "to cause destruction" before Aeona destroys the book. Aeona states that the Executors only use them for their power and that Tana must be lucky that she was not chosen so she does not have to bear the burden of being a transcendent. As she leaves, Tana creates another book as she has the power of creation.
Aeona then went mad with power, destroying 7 of Grandis' races, possibly even more, as stated by Melange as she left no traces of her actions. Tana then faces Aeona and seemingly kills her. Tana is then able to hear the voice Aeona could hear, thus the Executors that stood witness gave her the title of Aeona and transcendent of Light of Grandis. Tana refuses the name and abandons her duties as the Transcendent, vowing to live for herself. She eventually leaves Grandis and arrives in Maple World, where she stumbles into kingdom of Kritias, where the past events seen at Morass take place.
In Esfera, Will recovers Tana and transforms her into the white sun for the new world. The Alliance realizes that the Black Mage, within the black moon overhead the Arcane River, seeks to fuse the white sun with the black moon in order to take Tana's powers, granting him the powers of both light and darkness so that he can create a new world. The player, after defeating Will, refuses to kill Tana to stop the ritual, believing that there was another way to save everyone, including Tana. The ritual succeeds, and the Black Mage absorbs Tana's powers, making him the Transcendent of Light of both Maple World and Grandis.
Tana appears briefly near the end of the Limina storyline, as the Black Mage is entering the Genesis Crux. She gives the player words of encouragement to defeat the Black Mage once and for all.
- GlobalMS named the Black Mage's two knights of Creation and Destruction (Aeonian Rise and Tanadian Ruin) after Aeona and Tana.