Known facts.

[the_original]

The Original Ion.

Last name isn't known. What is known is he is originally from Malkuth, an impoverished family and was found and placed into his position by the Score. His birth Score stated he would be Fon Master, and Yulia's Score confirmed this when read.

What they didn't tell him right away was Yulia's Score also said he would die at age 12. It's also not known, but assumed headcanon that the disease was entirely curable.

While that sounds extraordinarily cruel and pointless, keep in mind that all were taught to follow Yulia's Score. Having hidden the Seventh Fonstone, everyone assumed it told of Auldrant's prosperity as promised at the end of the Sixth Fonstone, therefore; as long as everything was done to make sure Yulia's Score was followed, the entire world would benefit. That included many pointless and avoidable tragedies that occurred simply because Yulia saw it in her Score.

Therefore, he was kept alive, but only until he got closer to that particular age. He'd been introduced to Arietta at age 6 apparently, and fancied her akin to a pet from her wild nature. She didn't know of the Score, which Ion already hated at this time, and therefore she became his Fon Master Guardian.

There's a lot of good headcanon here involving the Score and more reasons for Ion and others to hate or dislike the Score;

The fact that Nephry was told to marry another; this might have been Karl V paying the Order to tell her this, and not knowing the Order wanted Peony on the throne at all costs anyway. This might also explain why Peony was moved away to Keterburg; they had the other heirs killed and made to look like they'd done it to eachother.

There's more, but this is Ion's story.

Dist also joined the Oracle Knights around the time Ion was introduced to Arietta, and with Van having knowledge of Fomicry, likely contacted both Mohs' and Dist to begin experiments on cloning Ion. The reason Mohs' likely would have agreed was that there wasn't a Fon Master listed after Ion, and keeping one alive, especially an easily controllable one was best for keeping the world on track with Yulia's Score.

Therefore, seven were made.

The first was killed out of Ion's rage over the idea, the fact that all of the Order accepted his fate without even trying to change it, and his own limited mortality. Whether he was actually an acceptable substitute is unknown, but might be likely as this was the first made with Ion's extracted data.
The second's condition was unknown, but died in Mt. Zaleho.
The third's condition was unknown, but died in Mt. Zaleho.
The fourth's condition was unknown, but died in Mt. Zaleho.
The fifth was noted for having better strength and agility than even the original Ion, but couldn't read the Score. It could use the Curse Mark, and a Daathic Fonic Arte that it dubbed Akashic Torment. It became Sync after Van found it wandering in Mt. Zaleho repeating the phrase, "The Synchronization Level is the problem..."
The sixth had abilities to use all the Daathic Fonic Artes, including reading the Score on a level similar to the Original Ion; but it was terribly uncoordinated and clumsy on a physical level. Mohs' found it still alive in Mt. Zaleho and took it; keeping it hidden from the rest of the world incase he needed a replacement that could read the Score. It was later dubbed Florian by Anise.
The seventh's fate was to replace Ion. It's magical and physical abilities were close to the original, but still fell somewhat short. Particularly it's endurance and constitution as it seemed to be unstable and not really up to using all the power supplied to the Original Ion. It could use all Daathic Fonic Artes, including one similar to Akashic Torment, and even reading the Score, but would tire after a single use or a short period of reading. It took the Original's name of Ion, and his life.

While the seventh might not have been the best choice; Ion was getting sicker, and weaker without any treatment whatsoever going on. Van, while he cared for and shared the same vision as Ion, likely let him die so he wouldn't have to see what would be done, and had suffered enough. Probably a "kindness" similar to the one he did for Arietta for never revealing her beloved Fon Master died two years before the start of the game. While it is likely true, this is still headcanon that Van did really and truly care for his tools, he still let them go when needed for the sake of the big picture; an Auldrant free of the Score.

Anyway, Ion and his Seventh Replica were gradually switched out for public gatherings so people could gradually get used to the slight difference in the mask the Original had shown to the world, and the genuine and naive kindness the Seventh had. Ion finally died on his deathbed, alone and away from his Guardian Arietta, who had already been moved away from the Seventh so she wouldn't know what was happening, and Anise Tatlin was personally chosen by the Seventh in her stead to serve him.

He died, still hating the world and the Score that had offered him this fate; a concept that all his surviving Replicas would inherent in one form or another, and finally realizing he'd found true love from someone that was untouched by the Score.

Van buried Ion in an unmarked grave, and his private mourning was the only ceremony the one true leader of Daath and the Order of Lorelei ever had.