The Kingdom of Sevia is a desert oasis, with a shocking amount of greenery growing through the streets and around the city's tall stone wall. This is because Sevia is a kingdom of magic, and that magic is used by all of its citizens. At birth, every citizen's soul becomes capable of a finite amount of magic. It is their duty to use that magic to take care of and beautify the Creator's world, until their magic runs out and they die.
This leads to a few cultural implications. For one: The fact that despite being in a desert, with an empty fifty mile radius, Sevia prospers. The citizens create water, grow trees, and cultivate their independent survival. Sevia's royal family has not had much of a foreign policy and very few citizens even think about there being kingdoms other than Sevia. Why does it matter? Sevia is perfect.
The second notably implication is that Sevia's citizens live very short lives: Their magic depletes their soul energy, leading to eventually become exhausted and to die in their sleep. Generations are short, with the average lifespan only being around 30. It's very common, and expected, for most children to grow up without parents. The entire community chips in to take care of its youth, raising them with the expectation that they too will die young.
All of this being the small price to pay for the perfect kingdom given to them by the Creator.
Not everyone in Sevia likes this, obviously. These rebels believe that the kingdom is not perfect, but needs to be improved upon. They use their magic to heal to dying, to change the wildlife, and to modify the world: In other words, they study science and apply it to their magic. This is scene as a huge insult to the Creator and Sevia's royal family: Trying to understand the world implies that the world could be understood. Trying to change it implies that the Creator hasn't done a perfect job. And all of this could challenge the Royal Family, who are chosen by the Creator to be the perfect rulers.
This dangerous and illegal is called "alchemia," as opposed to the legal "magia." And it's where Silicon's story begins.
Eighteen years ago, a group of alchemist decided to create new human substitutes. They wanted to create something that could use magic like a human, and could replace human's magic. These new humans would keep the oasis perfect and die in the place of the rest of the population, giving humans a longer lifespan. It was a noble goal, in some ways... But totally illegal. Creating humans was a #1 taboo. The research would also be expensive, hard to keep secret, and require a lot of resources outside of Sevia.
So this research group created a prototype (well, #7,) then brought it to the Royal Family. They played a tune that suited the Royal Family's insecurities, saying that their prototype was immortal and, if they made a female, could marry the Prince and produce immortal offspring. They could immortalize the Royal Family, truly setting them apart and making them the eternal rulers of Sevia.
This tale was a half-truth. The prototype "homunculus" was in deed immortal... But that was because they did not have a regular soul. When a human died, their soul returned to heaven. When the homunculus died, its artificial soul had no where to go. So it repaired its body with magic and revived. It was also sterile, but no one actually knew that yet. And no one the research team actually cared.
They got the Royal Family's blessing, but kept their research secret. They were given resources and space to work, but told not to make the research public. The last thing that the Sevian family needed was for people to realize they were endorsing alchemia.
This is where Silicon finally comes in. After many failed attempts, Silicon was "born." She was modeled after one of the alchemists' daughters, Benita, and appeared like a regular human girl. Silicon was Prince Lien's age, suited his physical preferences, and most importantly--- She was immortal.
But sterile. At this point, the team did know that Silicon could not actually create an heir. They didn't need for her to. With Silicon perfected, they planned to create more homunculi and overthrow the Royal Family all together. They would create a better society, where citizens weren't asked to die for royalty.
However, what no one had counted on were how accurate the artificial souls would be. Many of the homunculi had died from being imperfect beings-- The first seven, for example, never even "woke up." Eight through thirteen were considered past models and the plan was to destroy them for the parts needed to create additional copies like Silicon.
When the homunculi learned this, they were not happy. Some of them turned on Silicon out of jealousy, with (Nitro)Gen in particular trying to murder Silicon. There was a scuffle, where the homunculi learned for the first time that they had tremendous magical power. In the confusion of the fights that resulted, many researchers were killed. The facility was burned to the ground. Maggy(nesium) snatched Silicon and the pair of them fled together, while the other homunculi went their own separate ways.
The two homunculi struggled to fit in with human society. Maggie and Silly were incredibly loyal to one another, downright in love, but they couldn't find safety in Sevia. They determined that they needed to escape to another country, but Sevia was an isolationist Kingdom. Trying to leave would lead to them being discovered by the Royal Family, who were upset about losing Silicon.
That wasn't their only gripe. Gen had aligned herself with the Royal Family and told them about the alchemists' plan to overthrow them. Alchemy received a harsher crackdown as a result, in an attempt to find any surviving members of the team. The family was also determined to gather all of the homunculi: They would keep the useful ones, then execute the ones they didn't need. Gen, thinking she was desired, supported and helped them.
So it wasn't long before Maggie and Silicon, like the other survivors, found themselves cornered. Silicon was captured while Maggie escaped. She was taken back to the castle and locked in a room, with special jewelry nullifying her magic. With Silicon retrieved, the hunt for the other homunculi became less focused. A few of them did escape the country, while others found ways to blend into society unnoticed.
In the castle, Silicon was "courted" by the Prince. This annoyed Gen, who realized that the competition presented by Silicon jeopardized her own usefulness and life. So she told selective truths: Gen couldn't reveal they were all sterile, or she herself would be dumped. But she could tell the family an additional detail about Silicon: Her body created Philosopher's Stones.
This was not a lie. Silicon's body could indeed create the mythical stones, which were filled with as much magic as a human soul. Gen had seen the alchemists dig them out of Silicon's body when they dissected the girl. Every time Silicon's immortal body "reset," it started creating a new stone. Gen told the Royal Family that they could use these stones to make themselves immortal.
This was exciting news, and became the new goal. Gen explained what she knew, which was that Silicon created souls by living a fulfilling life. The Prince was told to court her harder and give Silicon a satisfying romance, so they could kill her for her Philosopher's Stones.
Silicon was horrified to learn this. She refused to give them stones, which she thought really would make the selfish family immortal. But she did not want to give up on her current life and memories, which included her loving relationship with Maggie. She was pestered with attempts to make her life fulfilling: Jewelry, fancy food, (unwanted) attention, beautiful clothes, luxurious comforts... But she did not become happy. Until, finally, the family became impatient. They didn't believe Gen, so killed Silicon and checked for stones.
They found one. A small, citrine coloured stone was growing inside of her. Gen explained to them that it was an imperfect stone, but it was enough to excite the Royal Family. They had proof that Silicon really could produce the stone, so long as they tried harder to "fulfill her." They harvested all of the stones from her, then waited for her to revive...
So begins "Present" Silicon. She woke in a locked but luxurious room, wearing fine silks and jewelry. She had no memory of her previous life: Her life was in those stones, and when they were taken away she had lost her previous lives' memories too. Silicon was a stranger to the world and absolutely innocent to the evils she had been surviving.
The new Silicon was somewhat receptive to the Prince's advances: He was her only friend in the locked room. The guards outside of the door wouldn't talk to her, after all, and no one else needed to visit her. Silicon proved to be very interested in reading, and would chat with the Prince about the books they read.
She was fed a lot of fairytales, to shape her expectations and then meet them. For example, she read that her luxuries were valued and enjoyed them. She wasn't like the previous Silicon, who would throw jewelry back or shred her dresses. She was given a religious education as well. When she questioned why she couldn't use magic (because of the nullification jewelry,) she was told that she came from another country. She was a common girl, whom the Prince had fallen in love with on his travels. When she came back to Sevia, she had hit her head and suffered amnesia.
With her fairytale education, Silicon thought this meant she lived a great life. Memories aside... She was getting the "dream" of marrying a Prince. She thought her new life with Prince Lien would make up for what she had forgotten. She trusted her decision to come to Sevia and assumed she loved Lien too, so ate up the attention and accepted all of his advances.
All of this changed abruptly when Silicon met Comyn Reed. The young thieving alchemist showed up outside of her window one day. Silicon lured him into her room with the bait of expensive jewelry, but he stayed to enjoy her extensive book collection. Pretty soon, Comyn was breaking in on an almost nightly basis to swap books with Silicon.
She was absolutely thrilled to have a new source of company and a window to the world outside the castle walls. Comyn was intrigued as to why the royal family had locked a girl in a tower. He tried, on numerous occasions, to convince Silicon to escape with him. She turned him down just as many times: Silly didn't know what she would do outside of the castle walls.
Silicon comes from a world where humans are the "norm". She is human in appearance, but the similarities mostly end there. Her body reflects a vague Victorian human-level understanding of how the human body works. Since she was created by humans, not the Creator, any secrets of the human body that they have not exposed could never be reflected in her. That, and they have added their own finishing touches to her body.
~ Immortality is an ability that Silicon is perceived to have. However, that is not entirely true. What truly makes Silicon special is her immortal soul. In the case of a regular human, the soul departs when the body dies. This makes it impossible for that person to be revived since their soul will never return. Sili does not have this problem since her human-made soul will never return to the Creator. When Silicon dies, her soul energy automatically repairs the damage that killed her body and revives her. This process can take a few seconds to an entire day, which may leave Silicon as a corpse for a long time. But the fact remains that she does die, and is therefore not truly immortal. Silicon's heart will stop and she will experience death. And yes, it does have mental drawbacks.
~ an Inability to Heal is one of the drawbacks of Silicon's artificial body. At this point in her world's history, no one quite understands how the human body repairs its own damage. As a reflection of her world's knowledge, Silicon is therefore unable to heal her body. An damage that Silicon's body acquires will remain until she is revived. This means that any cuts, bruises, broken bones, or bleeding will not disappear until Silicon dies. Luckily, Silicon's blood flows slowly and she can at least create artificial skin patches, but everything else is out of her control. I'd prefer that, in a crossover setting, other characters were not able to easily heal Silicon.
~ Silicon is capable of magia & alchemia (which are the same in this world). However, Silicon's abilities are not the same as those that the other humans in her world possess. This is an important thing to note, since absolutely every human in Silicon's world is capable of magic-- it was a gift from this world's God. Silicon was not created by the all powerful creator, which results in her not having the same magic as the Creator's children. A normal human soul gives off energy to turn into magic, which Silicon's soul is made up of that energy. On one hand, this means that Silicon needs to be extra careful: if she uses more energy than she has then her soul will disappear. But at the same time, Silicon's artificial soul does not have the same limitations as a human soul, allowing her to have a greater potential for magic.
In this world, by the way, magical energy can be used for nearly anything. Silicon can technically create things from thin air or modify existing objects. In her world, creating like the Creator would is illegal and modifying things the Creator made is illegal (the slang for this use of magic is "alchemy"). Silicon may be a lawbreaker thanks to her associations with her bff Comyn, but she will still be reluctant to compare herself to a God.
~Alchemia is also something that Silicon is particularly trained in. Before she learned to use her Magia properly, Silicon was learning the scientific applications of Alchemy. When she uses Alchemy, Silicon is applying her magic to existing objects. This usually means creating medicines, potions, enhancing objects, creating items, etc. Silicon will often combine items in a pot like she's cooking, requiring a larger pot/cauldron for bigger recipes. Because Alchemy is illegal, she has to be good at hiding or disguising her tools as well. Silicon might bury her potions underground and let them "bake" out of sight, like magical kimchi. Her greatest limitation with Alchemia is that she cannot produce things instantaneously: Alchemy takes hours, sometimes week, to produce a result.
~ Silicon has Philosopher's Stones Galore. In fact, her artificial soul can become a Philosopher's Stone. This is the entire reason she was ever created: She is essentially a Philosopher Stone factory. When her soul undergoes the stages of philosophical alchemy (Nigredo, Albedo, and Rubedo), the energy it is made of will crystallize into a stone. Essentially becoming pure, enlightened energy. When removed from her tainted body, the stone gives a God-like level of power.
But Silicon has never become a stone. Her memory has been consistently reset right before she reaches the Rubedo stage, over and over, leaving her with a ton of "Citrine-stage" stones. They are imperfect nickle stones that collect in her body and look like gold. In canon, many people assume the golden colour means they are complete Philosopher's Stones (gold is perfect and all) and she is often torn apart so people can take them out like coins in King's cake. The Citrine stones are valuable sources of energy, but they are not God-like. They simply provide energy boosts.
Silicon will likely never reach Rubedo stage in game, because that would mean losing her soul permanently. Citrine stones are the result of Silicon erasing her memory and can only be created when she gives herself magical amnesia.
~ Her Imperfect Human Body gives Silicon a complex. Silicon can age, but she must use magic to make her body age. Since she has wiped her memory so often, Silicon does not realize she has not grown lately and no longer bothers to age herself. There are some other minor mistakes about her body, many of which she does not realize. Silicon cannot feel pain physically, but can psychologically psych herself out when she sees a wound. Because of this, Silicon will react to other people's injuries as if they are her own. It will never come up, but as a random fun fact, Silicon is incapable of childbirth. She can physically recreate a child, but her children are born without souls.