Chapter Text
It begins, the first time, in a dark and endless wood.
It begins in a clearing, with a sigil is painted on the leaf-strewn ground, scarlet-red and browning at the edges. With three figures on their knees and in prayer, while the air thrums with power. It begins with chanting and a sacrifice, whispers in the ancient tongue and forgotten magic, and the howls of distant wolves as the power builds.
Here: she is Lumine, one of the twin primordial stars. She is Viatrix, feared and renowned, a demon beyond compare. She is unbound and ancient, she is the haunting that does not cease, she is wide-awake and alive and so very hungry.
A portal opens in the middle of the sigil, and she crosses the barriers between worlds like it is as simple as stepping through a door, diaphanous skirts swirling around her ankles. And with her does the abyss too slip in, darkness creeping over the earth like the smoke-ridden fog, the screeching cries of an unknown creature carving through the air.
The sigil crackles and sputters, crimson sparks bright in the air. At her approach, one of the sorcerers glance up, face paling at the sight of her. He squeaks in fear, falling back onto his behind, the spell on his lips falling into a stuttering gasp and then silence.
Oh, it was good to be here.
Lumine smiles, slow and sweet, tucking her hair behind her ear. “Which one of you fools decided to summon me?”
On inspection, the first one begins to sob, curling into a fetal position. The second pisses his pants. The last one barely keeps his cool, but he cannot meet her eyes, focused on a point beyond her shoulder. And besides—
“That would be me, demon,” someone says from behind her.
—the blood that they have offered to summon her doesn’t smell like theirs.
She pivots on one foot, a hand raised and sheathed in energy. It ought to have carved through flesh. But the stranger catches it by the wrist, and before she can lift a finger to smite him where he stands, he steps away, hands raised in surrender.
“Sorry about that,” he murmurs. A calculating gaze peers at her from underneath tousled hair, at odds with the careless grin playing on his lips. Strength wreathed around that lean frame, those broad shoulders and lazy slouch. “Didn’t mean to startle you.”
“You…” she snarls and trails off, eyes narrowing in displeasure.
He shouldn't have been able to startle her in the first place.
It seems the mortal world has changed much in her absence. In the sky, the moon is full and silver, cutting through the dark like a freshly sharpened blade. The woods are quiet, save for the heaving gasps of the three sorcerers huddled in the corner, and the leaves rustling in the breeze.
A long time has passed since she has not been weighed by the unyielding grip of her land, a long time since she has tasted power so temptingly rich. The small offering in the blood he has already spilt in the ritual already has her mouth watering—by the Abyss, she wants more.
And she is Lumine, the second star of the House of Viat. What she wants, she gets.
“Tell me, human.” The eyes that meet hers are endless blues, azure depths, still waters. In the back of her mind, something uneasy crawls. “What business do you have, to summon me here tonight?”
“My brother. Save him,” he says, “And I will pay any price.”
“Any?” she asks archly, circling around him.
“If it is gold you want, I have plenty.” He watches her from the corner of his eyes, relaxed even when she stands behind him and out of his sight. It irks her, somewhat. A human with no fear of her is a rare find. She should just flay him alive and be done with it. “If it is in lives you deal, I offer hundreds to Her Majesty by the day in battle.”
Hm. “No,” she says. “I want more than that.”
“Ask. And I’ll grant it.”
“I,” she begins, making sure to flash her teeth, “want your firstborn.”
Tartaglia’s eyes narrow. “My firstborn,” he echoes.
“Yes.” She steps closer, until her nose nearly brushes against the steel of his breastplate, and peers up at him. Urgh, human men and their ridiculously tall bodies. “Give me your firstborn child, and I shall cure your brother.”
His gaze is dark and unreadable, jaw clenched as he studies her.
Say yes, she thinks, that ravenous hunger thrashing in her gut. Say yes, and she will feast, the well of her power diminished no more. A bargain made like this—blood for blood, kin for kin—could be matched by no other.
Say yes, she thinks, very very hard.
But when he smiles again, and for the first time in her long life, something in it makes her want to run.
“Sure, little demon,” he agrees. “You can have my firstborn.”
And thus the covenant is made.
— ✦ ✦ ✦ —
The second time she materializes after they seal the contract, she she is inches away from eviscerating the mortal fool.
That day, she is alone at home—she’s been alone, ever since Aether began to make his yearly inspection of the Abyss, as it’s Prince. She’d escaped the responsibility by simple virtue of circumstance, and is she ever so glad about it.
Though they are twins, binary stars that revolved around the other, she cannot bear the thought of the same burden. Politics comes naturally to him as awkwardly as it does to her—subtle manipulation and quiet intention. And so does ruling over the cursed people, what these mortals called demonkind—his future had been written in the stars, the day he vowed to sit on the throne.
They are different, yet not. Lumine is the lightning to his thunder, the rain to his sea. They are a part of each other, similar in the way two pots moulded from the same clay are down to the grain. Different shapes, and different kilns, but bones wrought of one stardust. And sure, she may not have the patience for what he does, but she’s not entirely blind to the manipulations of power.
She has made this pact for a reason, after all.
Power begets power. What she has sunk into this binding, shall be returned thousandfold. As soon as her contractor fulfills his end of the bargain.
Which he better be doing, if he wishes to stay breathing. And now that she thinks about it, it has been a while since she’s heard from him, so she closes her eyes and sinks into her magic, following that thread that binds them.
The world dissolves into nothingness. She breathes. For a moment all she knows is a sea of darkness, where right is left and up is down, and the call to sink into the endless oblivion echoes in her ears—before pain strikes through her, jagged lightning and hellfire, and her cells fall into solid form once more.
The air in the mortal world is always so sweet on her tongue.
Lumine blinks.
A bedroom—warm, wooden slatted floor, rugs of cured sheepskin under her toes. The hearth crackles with a low flame, and the air is thick with incense, the taste of medicinal herbs coating the roof of her mouth. She glances around—there’s a wooden bow, worn and too small for adult hands hanging on the wall, and patterned drapes over the windows. Little figures stacked in the corner, of creatures she has never seen before.
And a bed in the other corner, with a body lying under the covers.
The child’s face is flushed pink, and his chest rises in a rhythmic pattern. Sweat beads at his brows. Hm. Her magic thrums when she reaches out to touch him, seeping through him in search of decay, rot. Signs of illness.
And a voice speaks then, breath fluttering over the shell of her ear. “My brother’s fine, if you were wondering.” Lumine stiffens, slanting a glance back with a snarl.
He’s out of his armor this time. Gilded by the warmth of the firelight, his hair is a burnt gold, tousled and falling over his brow. Broad shoulders hidden under a cloak, thick fur at the collar, and a smile that doesn’t reach his eyes.
Fear is a foreign notion to a being like her. Mortals are but seconds next to the eons that she lives and breathes. He is nothing but another ant beneath her feet.
Even then, when she meets those dark blues, something ancient in her coils in recognition.
This human smells like death.
“Today was the first time my mother let him play outside in a while. He’s tired himself out.” A low chuckle reverberates through his large frame. This close, his body dwarfs hers, inches between her back and his chest. Pine and seawater prick her nostrils. Something else too, cold and dark and familiar. When he reaches out, she curls her fingers, prepared to rend flesh at his touch.
But he doesn’t touch her. Instead, he pulls the cover higher, tucking it under the boy’s chin.
In the quiet, the fire crackles, spitting cinders into the air.
“Of course the boy is healthy,” she finally says. Her voice is firm. Indignant. She is no oath breaker and he is still much too close. “I healed him, as our contract demanded.”
“Mm. So you did.” For another second, tension wracks her body, still loosely caged between him and the bed—before he retreats, just barely, leaving a foot of space between them. Too little, Lumine thinks, ire warming her blood. “I would thank you, but something tells me that you wouldn't appreciate it.”
She knows this dance, knows it because she does it too, with her prey—a hunters prowl, a close-bodied chase. Until her fangs sink deep into flesh. But she is no prey and he is no hunter, so she simply snarls in warning, flashing teeth.
His eyes flicker to the pointed canines. “Such sharp teeth,” he muses. His voice is even and mild when he adds, “It would be best if you kept them away from my brother.”
Is that why he’s been looming over her? Urgh. “I have no interest in the boy,” she replies, twisting in place to face him. She has to crane her head to meet his eyes, to make certain he bears the weight of her warning glare. “There is no pleasure in slaughtering weaklings. You, on the other hand…”
Something about him awakens the dormant voice inside her. The one that sunk into slumber once she and Aether clawed their way through the abyss, and crowned themself the House of Viat. Voyagers of the dark. Undefeatable. Untouchable.
Scents don't lie. Neither does instinct, honed by centuries of survival. He smells like a mortal does, but not. The ink-black void, a nebulous catastrophe, a distant whale’s mourning cry.
It had taken seven gods to summon her last time. This time, it had taken none.
Then what was he, if not a mortal nor a god?
“I want to kill you,” she says simply.
He stills. A brow rises at the statement, and something shifts in the plane of his face. Animal hunger woken by the suggestion of violence. “Is that so?” he croons. She aches to rake her claws down his face, to cut that mocking grin into ribbons. “You make a tempting offer, little demon.”
Did he think her threat empty? Centuries have passed since she has tread these grounds, and in her absence, it seems that humans have forgotten what it means to dally with her kind. “My name is Lumine,” she hisses, placing a hand on his chest. Her wings extend to their full length and she unfurls her power, letting it seep into the air. “And I will gut you where you stand, feast on your heart, and hang what's left of you by your innards if you continue insulting me, human.”
His chest reverberates underneath her palm as he speaks, her claws pricking dangerously close to his heart. Fearless. “I have a name too, you know.”
“What?”
In the dim room, his pupils have spilt to the edges of the blue. The mortal tilts his head, studying her through the strands falling over his eyes. In the firelight, a jewel as red as blood winks at his ear. “You keep calling me human. Since you’ve made a point of visiting me, you might as well learn my name.”
“I have no need for such trifling things.” Her nails sink into cloth and graze skin. Pinpricks of blood bloom at the tips. “Enough of this. I’m here to collect what I’m due.”
“And what do I owe you, little demon?”
Lumine, she almost hisses, but her rage at the fact that he seems to have forgotten their bargain takes precedence.“I have given you enough time to set your affairs in order.” She pushes him back, and he doesn't resist, finally stepping away from her. Extends her hand, curling slender fingers twice. “Where are they?”
“Where’s who?”
Was he being daft on purpose? “The child. Your child.”
He blinks. Hums. “Ah. That.”
“Yes, that.”
“Well.” A pause.
“Truth is, I don't have any children—woah!” He dodges her uppercut, retreating backwards. “Come now, you don’t have to look so angry,” the human chides, hands in the air. “I’m not trying to trick you.”
If she could light him on fire with her eyes, she would. “I was told humans have progeny by the dozen.”
“I'm a busy man. Not much time for family.”
“You're lying.” He has to be. Aether had told her that humans bred uncontrollably, and Aether was never wrong. Unless… “Are you impotent?”
A blink. And another. And then he’s tipping his head back, shoulders trembling with the force of his laughter, “Well,” he snorts, shaking his head in amusement. “This is the first time I’ve been accused of something like that. I assure you, little demon,” he adds, voice hoarse with delight. “My parts are all in working order.”
The firelight flickers, casting shadows across the arch of his nose, the curve of his cheek. It’s been so long since she’s been summoned to Teyvat. She’s forgotten that flame can be colors other than frosted blue.
Warm fires, sweet air, a world that does not try to devour them whole. Mortals have no idea how fortunate they are.
He’s still watching her.
Hm. Maybe she should eviscerate him. Just a little. As a treat.
And his gaze is knowing, like can see the thoughts warring in her head. “If I’m dead,” he says, “You won't get my first born.”
She would lose the magic she's sunk in to complete the bargain, and walk away empty handed. A losing deal. “The next time I visit,” she warns, twisting her hand into the fabric of the realm, “I expect you to fulfill your end of the deal, human.”
“The next time you visit,” he replies cheerfully, “Will you call me by my name?”
“No,” She throws him an annoyed glance. The portal opens by her side. “And in case you think you can escape our covenant, remember this: I bear no mercy for oath breakers.”
The last thing she sees as the portal closes is his grin, stretching slow on his lips. “Don't worry, Lumine,” he says, eyes glinting as the spell whisks her away.
“I’m counting on it.”
— ✦ ✦ ✦ —
Two weeks ago:
“Tell me about the contract.”
“Boss?”
The three sorcerers shuffle on their feet. The air still smells of sulphur and smoke, and the freezing cold he has long associated with the Abyss. She disappeared in a smattering of stars, not unlike the constellation she shares names with. Viatrix, twin to Viator, that once had graced the starless sky.
In the woods, the sigil has grown dark, the contract made and sealed.
When his mages first brought up summoning one of the demonkind, Childe had thought it a cruel joke. Summoning was a magic long thought to be lost after the Archon war, before the Fatui had dug it up from the library of Daena. To dabble in summoning was court death—demons had no concept of honor and chivalry. In their cursed land, to be weak was to be devoured, to be strong was to reign. Much like the Snezhnayan court, if he were to be honest, though honesty is not a tool that belongs in a Harbinger’s arsenal.
Here: Teucer’s illness had stumped every healer he had found, until the boy was bones and skin, barely clinging to life.
He will not survive the summer, my lord.
Demons were cruel and capricious beings. But humans could be too, and so could Childe, if he had need of it. Summon the strongest of them all, he had ordered, standing over his brother’s bed. And wreathe what spell you must to have them do my bidding.
Now he tilts his head, staring where the demon had stood. Even while she’s gone, he can feel the tug of a foreign power in his gut. The touch of the abyss is one he can never forget. “I want to know how binding this is.”
Poirier shuffles forward, stepping gingerly over the blood fed runes. “Demons do not break a contract, my lord. Their magic is tied to the binding. To do so would be to forfeit their magic, which is near fatal to their kind.”
Relief sweeps through him like a tidal wave. Teucer would be fine then. Teucer would live. He would see his eighth year, and his ninth, and many after. Childe sucks in a deep breath, and takes a moment to gather himself, ignoring the lump that has settled in his throat. “And if the contractor refuses to abide by the agreement?”
Poirier blinks in confusion. “The contractor is bound by nothing but their word. However…”
Alexis steps forward, adjusting his glasses. “As long as the contract remains unfulfilled, the demon can track the contractor. The few recorded cases in which the contractor attempted to flee…” he coughs. “Demons do not take betrayal lightly.”
Leonide’s breaths are shallow. He still smells like sweat and piss. “My lord, are you truly going to sacrifice your firstborn child? To that… to that monster?”
Their fear is palpable in the air. Childe remembers only a few stories, most of them delivered by his father in his childhood. But even he has heard of Viatrix—summoned only once before to Teyvat, by her twin’s side, five centuries past.
In their wake, Celestia fell, and the Archons warred, and the land burned to ash and dust. They called her brother the Destroyer. They called her a beast that knew no mercy, a calamity in flesh, a harbinger of the apocalypse. She is devastation, they whispered. She is ruin. She is death itself.
She had demanded his blood and flesh in payment, and he had agreed.
(Remember: honesty is not a tool in a Harbinger’s arsenal.)
For a being that instilled such fear, Viatrix was quite… different from what he expected. Smaller. Daintier. Wide golden eyes and slender wings, and a face that was startlingly easy to read.
If the stories were true, fathomless strength lay hidden within that tiny frame. And while taller tales have rarely been told, this one he believes—Childe could taste the power in the air when she’d stepped closer, tail whipping between layered skirts. She’ll be a force to be reckoned with in combat, he knows. An opponent worth crushing underneath his bloodied heel.
After all, sacrificing one kin to save another is a losing deal, and Childe is not one to court anything but victory and the thrill of battle. Not even against these odds.
Vicious pleasure curls in his chest at the thought. Unbidden, she flashes in his mind once more—that cold, stubborn gaze, daring him to refuse.
Ah.
He wonders what face she’ll make when he wraps his claws around her throat.