The Twili Race

A small civilized tribe of Twili people resides in the land of Hyrule. Though there is not much known about their past it is known they all once came from a different realm, the Twilight realm. It's been hundreds of years since the harmonious merge of Twilight and Light realm and all Twili that call Hyrule their home have long forgotten about their place of origin.
Twili of the modern Hyrule time were not frequently trained in any special combat (unless they joined the royal forces.) nor were they ever trained in using magic as it had been long forgotten that the Twili race is very susceptible to magical properties. Overall the race that remains within Hyrule live a quiet and peaceful life alongside everyone else----
Graxi was born within this society and lived out her young life without much of a fuss. Except for having the complete opposite sleeping schedule a normal Hylian would have, Graxi had a very normal upbringing with two supportive and loving parents.

Current Mentality

Graxi's personality can be one that's hard to pin. Though "crazy", "mad", and "insane" can all be good descriptors of her current state none of them seem to dive deep enough into her mentality.
It should be noted that before the incident Graxi was a kind and gentle individual often splitting her time evenly between her scientific craft and friends. Her favorite pass time was indulging in the friendly rivalry she had with Purah.
Now, even though she can still be perceived as playful and curious, she is a completely twisted version of her older self. Outside of her craft, she enjoys the occasional bloodshed and the tortured screams of her weekly experiments.
Only on very rare occasions can one get a glimpse of Graxi's former self when she is found alone, hurt, and vulnerable while having painful flashbacks of the past. During these times one can conclude that there is still an old part of her left trapped in the chaotic storm that heavily regrets everything she's done.

If anyone wants to read some shitty fanfic of an OC I'll link it below. Otherwise here's the super condensed version.

Graxi was a respected scientist within Hyrule, her closest friends being Impa and Purah. She spent her days working for the royal family by helping out with medical research along with aiding in the Ancient Sheikah Technology research - rivaling with Purah and Robbie in a friendly manner. Wanting to know more about her Twili past and the technology it once held she asked the royal family for permission to research this second technology. The royal family denied her wish and warned Graxi to not look into it further as Hyrule had a not so great past with the Twilight Realm and the nameless king that once ruled it. Fearing that researching such history would only surface old wounds and possibly awaken an ancient horror.

Consumed by curiosity Graxi ignored the warnings fo the family and elders alike and set off to uncover the mysterious technology herself - swearing to herself that it was only the technology she was after not the history and legends.

Graxi had stumbled upon an old ruin on her researching journey and within it, she discovered an ancient helm (Zant's helm - though she is unaware). Only after trying it on did Graxi start to have hallucinations and visions. Making it back to her lab safely with the helm she slowly became more obsessed with researching the helm and the frequent visions. A worried Impa stopped by Graxi's room one night and noticed the helm along with the extensive documentation, in horror Impa, ran immediately to the royal family. Unsure as to why Impa acted as she did to the eerie helm Graxi hurriedly packed her research along with the helmet away to hide it once again within Hyrule.

Royal guards tracked Graxi down the following night - arresting her and throwing her in jail within Hyrule Castle. She was told the royal family would spare her life if she gave the location of the Usurper's helmet. Refusing Graxi spent the next couple of days in a cell while the royal family decided on what to do. While in this cell the visions and hallucinations became more frequent and clouded her mind. She often saw a tall shadowy figure looming over her - telling her to escape and take the helm back to the ruins with another.

After a bit, she hit a breaking point. The door to her cell creaked open as a guard entered to take her (it was unknown where she would be taken as at this point Graxi had lost all sense of her surroundings and all spoken word seemed to be garbled). With a swift kick and a surprise stab to the neck with a rusty scrap piece of metal, Graxi took down the guard and took his keys. Grabbing the guard's Halberd from the wall the Twili fought her way through the castle and out into the yards of Hyrule. Severely beaten she made it back to the hiding spot of her research when one of her coworkers flanked her from behind. Noticing the girl was unarmed Graxi took this Hylian down as well - breaking her legs and rendering her unconscious. She drug the unconscious girl with her to the ruins.

Once at the ruins the girl was flung to the altar at the middle of the room, awake now she screamed in pain and begged Graxi to stop the sudden madness. Whispers that shortly turned to shouts told the Twili to kill the Hylian offering her blood and soul to open the long-forgotten Twilight realm. Without hesitation, Graxi jammed the halberd into the heart of the girl and watched as her blood pooled and moved through the elaborate carvings. Causing the soft teal glow of the markings in the room to go red. Exhausted from the wounds and mental blows of the previous day Graxi collapsed alongside her lifeless friend only catching a glimpse of the massive shadow of a person developing before her.

She awoke within the Twilight realm inside a small ruined castle. There she found Zant and after a long boastful introduction of himself, he stated that Graxi now works for him. After a bit of back and forth and a handful of evil manipulation later - Graxi agreed. Back home many believed Graxi to be dead though some had an off feeling about her sudden disappearance paired with her uncharacteristic outburst. Shortly after this, the calamity happens (Breath of the Wilds) and both Graxi and Zant return to aid Ganon once they have developed a small army.