EON, often known as Millie, is the final remnants of the Deity of Sin's power in Gamindustri. Her true name is CFW Save, and she personifies the desires of game enthusiasts to preserve old, unsupported games that can no longer be played by legitimate means. In a way, she exists as a counterpart to Histoire, being a kind of record of Gamindustri's past through piracy and file-sharing.

EON is a young lady with long brown hair, deep blue eyes, and nearly snow-white skin. She most often dresses very similarly, if more modestly, to Vert, when said big sister isn't dressing her up and doting on her.

While in her ISO form, her hair and eye color change to silver and green respectively. Her usual processor unit, the Save Unit, resembles the appearance of Arfoire's true form.

EON was abandoned at the Lowee Basilicom of her Dimension as an infant exactly 1000 years after the defeat of the Deity of Sin, with only a note reading "forgive me", and a locket with the letters "EON" engraved in it, which nobody, not even Blanc, was able to open. Due to her apparent powers and birthplace matching the legend about the origin of Arfoire, the Basilicom believed her to be the reincarnation of the Deity of Sin, and the other CPU's and Candidates were called for council on how to deal with the infant. Despite strong encouragement from the Basilicom to simply kill the child before it could realize the destiny of destruction it was sure to bring upon Gamindustri, the CPU's, Vert in particular, absolutely refused such a horrible course of action. In order to placate the Basilicom, and keep the child safe, Vert convinced everyone to allow her to take the child with her to Leanbox, and raise her away from any so-called "destiny". Reluctantly, the Basilicom agreed, and the child was taken to live in Leanbox, though was often visited by the other CPU's to help take care of her. It was during this period that EON was given the nickname Millie by Neptune, saying that "an eon is like a million years". Despite Nepgear's correction that an eon is actually a billion years, the name stuck.

In her early childhood, she would often recall vivid, if brief, memories of events she was sure hadn't happened to her in her life in Gamindustri, and would even occasionally show knowledge of people or places that she should have no way of knowing, causing everyone (especially her) no small amount of confusion and concern. As time went on, however, these instances grew less and less frequent, until they eventually faded from EON's memory, and those who knew of her origins cautiously attributed the oddities to her potential legacy. Growing up with the contrast of a loving (and doting) big sister, and the mistrustful Basilicom staff, EON grew to be a kind but precocious individual, with a great desire to protect her home and family, and prove herself good. In hopes of being useful to her nation, she devoted her time to learning all she could about magic, seeking the tutelage of some of the strongest and most knowledgeable magic users in all of Gamindustri, including Histoire, the Oracle Mina, the Mad Magician, MAGES., and even the Lowee candidates themselves, Rom and Ram. One of her original attempts at "helping" was to use her copy powers to preserve not only magic, but the memories and even personalities of Leanbox's citizens. However, such behavior was immediately met with hostility by the Basilicom staff, and Vert made EON promise not to use her powers in such a manner again. She didn't yet fully understand why the Basilicom hated her so much, nor why she shouldn't use her powers, but she refused to give up on being of use to her friends and family.

Unfortunately for EON, the Basilicom's fears weren't so far off after all. EON's true name is "CFW Save", and though she is not a direct reincarnation of the Deity of Sin, she is indeed a manifestation of her power. Using what little Shares they still had, the remnants of ASIC worked throughout the centuries to create a dark Sharicite crystal, containing faith in the Deity of Sin and her ideals. Using this Sharicite, they conducted a forbidden ritual intended to "steal a spirit from above the heavens, and Re;Birth it in mortal form". With the success of the ritual, a child was born unto them, a dark CPU they hoped to forge into a perfect weapon against the Goddesses, and a vessel through which the Deity of Sin may one day return. However, feeling regret at her actions, and wishing to give the child a chance at her own life, the very mother of the newborn CPU stole her away in the night. Within the locket she was left with, the mother sealed an Arfoire Chip, which contained all of the CFW's dark power, placing a powerful ward upon it to ensure it could never be opened, represented by the phrase "Execute Operation: Null;", or EON. With her powers sealed, the mother brought her to the only place she thought the infant might have sanctuary: the Basilicom.

Eventually though, the spell weakened, and the locket opened, revealing to EON the truth of her dark power, and darker origin. Distraught, broken, and overwhelmed by the power of the Deity of Sin that invaded her being, she assumed the form of CFW Save, and almost went down the path of destruction that was planned for her so many years ago, only stopped when she copied the power of her big sister Vert, and feeling the warmth and love she still felt for her, rejected the Deity of Sin's influence once and for all, and forged her own path.

As she entered her young adult years, EON's desire to help and protect the citizens of Gamindustri only grew stronger. However, the more closely she observed the internal and external politics of the nations, the more she realized how broken they truly were. In every nation, the story was the same: those with power and wealth could do as they pleased and were beyond reproach, and those who did not had little choice but to put up with the abuse of the rich, or risk having their entire lives crash down around them. With each new business she investigated, she grew more and more sickened by the state of things, and decided that she had to do something about it.

Unfortunately, when she brought her concerns and findings to the other CPU's, she was met with only tired looks of resignation. They explained that despite their positions, it was frustratingly easy for the corrupt elements in their nations to work around any regulations or protections they put forth. When EON asked why they don't enforce those protections more forcefully, or even carry out their enforcement personally, the CPU's simply shook their heads, saying that ruling through force is the move of a tyrant, and if they were to do so, the people could easily be turned against them, causing even greater strife for their nations as a result.

EON was distraught. She knew that the CPU's were right, she knew that having them tighten their rule would cause more problems than it solved. But she also knew that she couldn't allow what she had seen to continue happening. Taking matters into her own hands, EON began holding public rallies calling for the better treatment of workers, and pressuring authorities to crack down harder on workplace violations, but no matter what she did, it seemed impossible to cause any meaningful change, as those at the top would simply use their influence to brush off any real consequences.

Little did EON know, she would be getting her chance to truly make a difference soon enough, in the worst way possible: one of her most vocal supporters at one of the larger corporations committed suicide. The apparent reason was inhumane levels of abuse from her coworkers and bosses. The corporation brushed the incident aside, and denied any prejudiced treatment of the employee because of her involvement in EON's campaign, but EON knew better, and had had enough. She returned to the CPU's one last time, and pleaded with them to help her put an end to the atrocities happening under their watch, but again, the CPU's denied being able to take any action.

EON was furious, but had already expected the outcome. She decided then and there that if the CPU's couldn't help, and the problems couldn't be fixed, there was only one remaining course of action: to burn it all to the ground, and rebuild from the ashes. On that day, the EON Multinational Union of Labor was born, with the singular goal of seizing control of all of Gamindustri. And in order to do such a thing, EON knew she would have to take the Shares for herself, and away from the corrupt monsters who had done so much harm to everyone. She also knew that it meant taking Shares away from the closest thing she had to family. Steeling her emotions, she set about recruiting members to her cause using the one thing she knew the whole of Gamindustri couldn't resist: Free games. For the first time in years, EON looked inwards, searching for a part of herself long since buried and forgotten. Harnessing Arfoire's lost power, EON did the unthinkable: she reactivated and transformed every Arfoire chip throughout all of Gamindustri, and declared herself the new Deity of Sin.

As with ASIC before it, people flocked to the organization, eager to get their hands on their very own new EMULator Chips. However, EON didn't stop at simple piracy. Instead, she promised protection and eternal life to all those who followed her, and that so long as they held their EMULator Chips, they could never truly die. In reality, this claim was made possible by combining the EMULator Chips with EON's own copy powers, reenacting her very first attempt at helping the citizens of Gamindustri on a global scale. EON was also able to use the chips to spy on events everywhere in the world, and could even cast magic through them to a limited degree. Taking in so much information all the time became progressively more strenuous, and there came a point where EON almost never deactivated her Save unit, using it to help process and delegate information throughout the world.

Having conquered the Deity of Sin and awakened fully to her powers, EON has access to a unique ability known as "ISO", short for Imitation Sacred Origin. With this power, EON is able to turn the data she has copied from a person or object into a virtual processor unit, which she can install as though using HDD. Though this does not grant her the same divine powers as a Goddess, it still confers a significant stat boost, and preserves the copied data for future use. It also often causes a shift in her personality, as she takes on the "spirit" of the processor unit's data. Once she has created a processor unit in this way, she is also able to physically manifest it and give it to another person, similar to Dengekiko and Famitsu's processor units. Shockingly, she is even able to use the ISO power on entire Dimensions, granting her a terrifying amount of control over the state of reality within them. She only uses these extremely dangerous processor units in times of dire need.

Theoretically, the full potential of EON's magical ability is limited only by the full potential of magic itself, due to her copying abilities. She has copied nearly all of the other CPU's skills, and can even create a Sharing Field like Uzume. Of the moves she has accumulated, she has a few techniques she tends to rely on most often.

SP Moves:

• Sylhet Repeat – 80 SP
  • Like Vert's Sylhet Spear, summons a magic spear to pierce the enemy. A second and third spear follow shortly after the first, like an echo.
• Kinestra Reversal – 120 SP
  • Hits the enemy multiple times with blade-like slashes of wind. Knocks the enemy back a distance.
• Save State – 200 SP
  • Alters the course of time itself, restoring all HP and SP a target has lost since their last turn. Can revive allies.

EXE Drive Skill: Rejected Legacy

EON: "I will not let my origins define me! I am Vert's little sister!"
EON activates her Save Processor Unit.

Formation Skill: Sisterly Bond
EON and Vert's Formation Skill.

EON appears to struggle, and assumes CFW Save's form, but is then gently hugged from behind by Vert.
Vert: "Don't worry. I won't let anything happen to my darling little sister."

EON changes back to her ISO form.
EON: "Big sister..."

Formation Skill: Sibling Rivalry
EON and Chika's Formation Skill.

EON is eagerly poised to charge the enemy.
EON: "I've got this one, big sister!"

• She not-so-secretly has a crush on Neptune, but would never say so out loud.