A sort of mad scientist AU where Y/N is, of course, a mad scientist. You suffer from chronic illness and you are desperate to make your experiments work but you struggle without help. You refuse to take on a human assistant out of a desire to not be treated as lesser--as if you can't conduct great, horrific experiments like the other crazed scientists. You stubbornly set yourself to work without any such succor in your tower and the days pass, wearing heavily on your soot marked hands and aching, waning body.
A solution appears right at your feet one evening while rummaging around for some material in the grimy streets (dead animals, toxic waste--the usual to carry out unethical tests) and discover two abandon animatronics in the back alley, left to rot and turn to rust. There's close to zilch hope for the two but you're not a mad scientist for no reason. You drag the endoskeletons home before prompting collapsing for a day or two after overextending yourself and paying the price.
Once you get your strength back (and cursing your weakness) you turn all your effort to cleaning and preparing the endoskeletons. The celestial model of the animatronics would be helpful in your work, no? One after the solar ball of gas which beams heat and light onto the world and the other after the gray rock which brightens the night and tugs on the tides. Sun and Moon. You solder wires and revamp the servos. You hold and handle the limbs and heads of the animatronics as if they were sleeping. Soon, they will wake.
There's just one problem. They need a spark. Not a bit of ember from fire or the first crack of electricity from a splitting fork of lightning. A spark of life. And you contain such material within yourself. It's dangerous to lord over life and play god, but you need them.
The night storms when you prepare the animatronics with their chassis open, lying down on tables. You are steady despite the buzz in your veins in the face of the most dangerous experiment you have conducted yet. With these two are your side, there will be many to come. You spill your blood, split away two pieces of your pulsing core, and set two tiny sparks of life from your beating heart into the animatronics. Your head spins with pain and hope. The hum of servos whirling to life touches your eardrums. A great rumble of thunder shakes the tower. Your vision is slowly swallowed by darkness as you start to collapse but before you fall, two glowing pairs of eyes open.
When you wake, you're in your bed, in the dark, and your chest is bandaged. You hardly have the strength to touch the blood-stains soaking into the gauze but a silver and blue hand stops you. Red eyes pierce you at your bedside, a dark personage holding your wrist. Standing on the other end of your bed is a tall figure with ghostly pale optics falling over you. Dread fills your marrow at what exactly you brought back from death. A raspy voice raises a question. Who are you?
The animatronics. They're alive. They want answers, and you are more than willing to supply them. You give a very detailed, breathy response about how this all came to be, and when you propose that they become your assistants in your endeavors, they silently share a glance and nod in unison.
Though you fear you got off to a rough start with them putting you into bed after making sure your heart was still beating, they prove to be everything you want—and more. They have no desire to return to whoever tossed them to the street and left them as scrap metal, and you finally have extra hands to hold together metal contraptions and nimble fingers to set the exact scalpel blade size you need in your hand when cutting into a carcass.
They do not infantilize you in your sickness, much to your aching relief. Sun, however, is poignant in reminding you that pushing yourself past your energy capability, such as walking into town and dragging back a metallic frame for a killing contraption, will result in you needing a day of recovery. Moon sharply remarks that willingly subjecting yourself to an overnight of experimenting with beating hearts and lightning strikes will most likely cause a pain flare, but they never stop you. They never decide for you. They see you—not the unending illness clawing at your edges and leaving its marks on your flesh.
Though you learn to manage yourself better—for science, of course. You request Sun's assistance for lifting heavy plates into place before you bolt and screw them down. He's all too cheerful to lend a hand. When it grows late, you allow Moon to lead you to bed before the fire in your muscles becomes a roaring inferno. He tells you softly that he's been recording the number of good and bad days you have, and that your flare-ups don't appear as often when you have a full night's rest. Your assistants are pleased—with the improvement in your experiments, of course.
It's rare, but sometimes you'll catch an odd sentence or two from Sun about where they were before, and how much nicer it is here. You give them much. You don't shout or throw things at them. He lays a hand over his chassis and smiles. Moon will look at you sometimes, and when you ask why he's staring, he says that you have never raised a hand to them. It's strange. He thought all mad scientists were the same. He's glad to be wrong.
You're glad they're with you too. Your science has never been madder and you don't lay through bad days alone anymore. You don't like talking about your chronic illness. The discussions you've had in the past with peers and professors revolved around how you're handling it and what it's doing to you today. Can you still do your work? It's not mad or experimental or new—it's just sad. Other people think you're sad and pitiful, and you would rather die trying to conduct a hazardous experiment than ever stop to tend to yourself.
Sun and Moon learn to take your mutters and curses in stride when another flare-up hits. They ask questions occasionally, wondering how long you've lived with this and if it would ever be cured but they seem to already suspect the answer. Sure, you've tried several times to manufacture an antidote to whatever poison sits in your veins, but such endeavors have only ended with you waking up, lying in your own vomit. They don't give you pity, not like the others have. No, Sun holds your hand between his large digits and asks if you've eaten anything yet. Moon touches your shoulder when you stare out of the circular window in your tower and asks if he can walk you to your bed.
They need you, and they know what great work you're doing here, crafting weapons of mass destruction, simmering glowing liquids, and putting together new creations—not like them, no. Nothing compares to your assistants.