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Diluc’s brow pinched in a frown as he brought steel crashing down upon bare steel. His opponent stood his ground; only sparrows twittered anxiously at the scuffle echoing across the otherwise deserted training ground.
“I want... I want to try something,” he panted. Unkempt flames escaped the sixteen-year-old’s ponytail: they hung limply in front of his face, which was flushed pink beneath the midsummer sun. “Something I read about a while ago.”
Kaeya slid his partner’s broadsword aside with practiced ease. “I’m listening.”
The fact that it was far too hot of an afternoon for combat exercise was no excuse for the Khaenri’ahn to let his guard down. Still, he couldn’t deny he was curious. He knew Diluc wouldn’t have dragged him away from the cool of the manor house—and the pricked ears of its maidservants—without a reason.
Stubborn ass that his foster brother was, though, Kaeya wouldn’t be surprised if said reason turned out to be part of some new Knights of Favonius training regime.
“Not here.” Diluc swallowed. Came up for breath. “Meet me in my room tonight, and I’ll explain everything.”
Oh?
That certainly didn’t sound like an invitation to extracurricular training. Not in its conventional forms, anyway.
Kaeya leaped into his next thrust and nearly knocked his opponent off-balance. He grinned. “Well, before you had me curious. Now you have my attention.”
Judging by the grimace he received in answer, Diluc was only too familiar with his attentions. But if the redhead didn’t want to lose ground in this fight, he would have to get his mind out of the bedroom. An aspirant knight couldn’t afford that kind of distraction.
Neither could a spy, come to think of it. Still... when it came to his favourite game, Kaeya found it a little too easy to make an exception.
In any case, tonight was sure to be interesting.
*
That evening, the Khaenri’ahn found his foster brother sitting cross-legged on the floor in his bedchamber.
Diluc had recently emerged from the bath. The lank wet hair tethered at the nape of his neck was the colour of old blood. A loose cotton undershirt had been rolled up over his elbows, and gaped at the pale skin of his throat: judging by such summer night’s attire, he’d seemingly forgotten about his own invitation.
So intent was the redhead on sharpening one of his hunting knives that he did not look up, even when Kaeya kicked the door closed.
As his company approached Diluc thumbed the edge of the knife. Frowned at a bead of red that bubbled up on his skin. “There’s a saying here in Mondstadt: ‘Blood is thicker than water.’
“Before Lady Vennessa founded the Favonius Order... Before the first stones were laid in Mondstadt, the land belonged to barbarian tribes. Ancient warriors swore oaths to one another with the blood they shed on the battlefield, and in their eyes, it made them closer even than brothers who’d shared the womb.”
Kaeya peered down at Diluc’s bowed head as the young man spoke. An empty washbasin was set upon the Sumeran rug between them, and distorted reflections swam in the polished silver. His own, and his foster brother’s. Closer even than brothers.
He arched an eyebrow. “So this is...?”
“The Church of Favonius condemned the practice,” Diluc went on. “But as a Ragnvindr of Mondstadt, it’s still part of my heritage. And if... when we pass the selection trials in the fall, we’ll be Knights—brothers-in-arms, like the warriors of old.”
Diluc lifted his head. Searched Kaeya’s politely detached expression with an unknown tightness to his own. “Would you do it?” he asked. “Would you swear a blood oath with me?”
I want to try something. Something I read about a while ago.
Could Kaeya claim to be surprised that this was what Diluc had had in mind when he’d uttered those words? The Khaenri’ahn probed the feelings surging within his breast, and he realized that wasn’t what troubled him.
Still, it seemed he wasn’t the only one intimately familiar with the shadows of his own past.
“I wouldn’t know what to say,” he hedged.
“It doesn’t matter,” Diluc told him. “I memorized one of the old oaths.”
Now that certainly didn’t surprise him. Biting back his grin, Kaeya settled on the floor across from Diluc.
“After you, then,” he said.
His unquestioning consent seemed to alleviate some of the tension from the hunch of the other man’s shoulders. Diluc nodded, stretching his right hand over the basin.
Kaeya watched the redhead clench his jaw. Then in sudden resolution Diluc slashed the hunting knife across his palm. His fingers spasmed into an unconscious fist; scarlet droplets spattered their concave mirror.
“Now you...”
Kaeya needed no further direction. He took the knife from his foster brother’s grip and carved a similar wound in his own right palm.
Diluc drew an unsteady breath. “Give me your hand.”
He reached across the basin, and Kaeya clasped his open hand. He heard Diluc hiss at the sting of their mingling blood; stared in some fascination at the colour dribbling down their joined wrists to pool in the depths of the basin.
He’d never noticed before. Or had never cared, perhaps. Still, it was strange to think that a Khaenri’ahn outcast bled just as brightly as a Mondstadter blueblood.
“I’ll say my oath first,” Diluc said lowly. He took a deep breath:
“Thus shall my arm bear my brother’s sword; let his enemies fear my wrath. And should he be cleaved from me, and lie clothed in the earth, in that same hour let the wings of darkness descend upon me. ...As the wind hears my words, so mote it be.”
As he spoke, the disquiet behind his whisper melted away. Kaeya imagined his foster brother were reciting some passage of rhetoric for Adelinde—some obtuse history that he, as usual, had conveniently forgotten to read ahead of their lesson. As usual, there was no spite in the young man’s affectation: Diluc simply believed every word of his ancestors’ glory. It was a faith that burned in the Vision strung at his left hip, in the blood Kaeya could feel pulsing against his scored palm.
It was that same faith that terrified him. One of these days, Kaeya knew he would have to be the one to open Diluc’s eyes to the truth.
Thrusting aside his premonition, the Khaenri’ahn grasped at nonchalance: “I should say the same, I presume?”
“You can say any oath you want,” Diluc told him. “Anything that feels right.”
Say any oath you want. It would be easy enough for the spy to pretend he’d never been asked to swear another oath. To pretend he’d never pledged so bitter a promise, in defiance of the gods that had taken everything from his people.
But oaths were too easily broken.
Say anything that feels right.
Kaeya looked across the basin at the young man for whom he’d forsaken his promise to his father a thousand times, for whose faith he’d turn a blind eye to the bloodstained annals of history.
“I’m yours,” he said quietly.
A wave of faint pink crested above Diluc’s collar. “Th—that’s not a warrior’s oath,” he managed to object.
“No. It’s just the truth.” Kaeya offered up a wry grin. Or is it? You tell me, Luc.
When the other man glanced away from him, the Khaenri’ahn switched tack. “Would you rather I swear by Barbatos, or another of your gods?”
Diluc didn’t answer. Kaeya felt the grip on his hand loosen as the redhead snatched at a neat pile of cloth strips lying near his knee.
“Hold still,” Diluc said mulishly.
Kaeya let the other man clean his wound, then dress it with salve and a swathe of bandages. Diluc’s jaw had clenched again; he set about his task with such admirable single-mindedness that Kaeya didn’t bother alerting him to the fact that he’d bound the topmost bandage too tight.
Yet when his foster brother withdrew, still intent on evading his eye, Kaeya beat his hand to the remaining dressings.
“My turn,” he offered.
Blood is thicker than water, Diluc had proclaimed. Ancient tradition aside, Kaeya wondered if he could have spoken so certainly while the gash in his hand flowed like spring runoff. The young man muttered a less-than-exalted oath as Kaeya pressed a wad of dressings into his palm.
“You cut too deep.” Kaeya knew Diluc didn’t need such a matter-of-fact reminder of his own folly, but he liked to see the redhead flush.
“It’s nothing. I’m fine.”
“You’d better be,” Kaeya acquiesced. “It’d be awkward explaining to Adelinde why you need her sewing kit.”
As he spoke he wrapped another strip of cloth over the reddening dressings. Despite the other man’s dismissal, Kaeya could feel the tension stewing beneath his skin. Of course, Diluc would be too proud to admit he was in pain.
One more layer ought to do it. Kaeya knew he could knot the bandage around Diluc’s knuckles without looking. Instead he leaned forward and caught the redhead’s lips.
It seemed Diluc hadn’t expected such a distraction. He tried to jerk away, overbalanced, and groped for a fisthold on Kaeya’s shirt—only to topple backward anyway, summarily dragging the Khaenri’ahn down on top of him.
Well. Now things were getting interesting.
Diluc gasped for breath, having hit the floor spread-eagled on his back. Kaeya took it as an invitation to kiss him properly.
It was almost too easy then to slip his tongue past Diluc’s parted lips. The short-lived muffle of the redhead’s protest only weakened his own case: they’d sparred too many times for Kaeya to believe Diluc was this much of a klutz. Far from it, judging by the alacrity with which the young man snared his fingers in his hair and parried him.
All the same, Kaeya made a point of pinning down his foster brother’s outstretched right wrist. Adelinde would be insufferable if she discovered blood on the rug, and Diluc was less practiced at lying than he.
Speaking of which…
If all Diluc had wanted was to hear the Khaenri’ahn make lip-service to loyalty, then he might as well have waited. They’d be swearing such vows when they took a knee for the Favonius Order. Well-read as he was, Diluc surely knew that much about the Knights’ initiation, yet he had still felt the need to emulate his tribal ancestors tonight. To assure himself that the pair were and always would be ‘closer even than brothers’.
Kaeya pulled back. Partly it was to let Diluc come up for air; mostly it was an excuse to sit astride his lap and study his slightly dazed game. Now this was a sight he could get used to: ‘kissed senseless’ was a good look for the redhead.
It was almost as if this was the only bond Diluc had had in mind when he’d said he would die for him.
The Khaenri’ahn tilted his head, his unshrouded eye hooded in consideration.
“Your heroes, Luc... these ancient warriors whose blood oaths made them closer than brothers. Let’s be honest. Just how close were they, really?”
Diluc’s eyes widened, and Kaeya knew the young man had been caught in his half-truth. “Most histories don’t go into... How did you—?”
“Call it a lucky guess.” Kaeya smirked, turning his attention to unbuttoning the front of the redhead’s undershirt. “Also, when you told me you wanted to try something, you blushed like a maid.”
Diluc was blushing the same way now, but Kaeya saw fit not to apprise him of that charming detail. He’d rather his foster brother’s rug didn’t become his funeral pyre. Especially when there were much more intriguing things Diluc might be coerced into doing to him tonight.
“You didn’t seem to think much of my oath earlier,” he murmured. He bent forward and nudged his lips against the redhead’s collarbone. “So—how about I show it to you instead?”
As Kaeya worked his way down the young man’s chest, lavishing attention upon the scars and blemishes that only he would ever get to see, he felt Diluc huff beneath him. “That’s not what I—”
“Oh?” Kaeya paused in between kissing his freckles—freckles he loved, if only because Diluc hated them. “Do you mean to tell me this demonstration is unnecessary? Should I stop?”
“N—no, I...” His red-faced game squirmed. “Just— Just shut up.”
Kaeya chuckled. He’d gladly do just that. There were better things he could be doing with his tongue, anyway.
*
Kaeya didn’t care for solemn oaths and ceremonies. Oaths could always be broken, he’d learned, and rites could ring hollow. Over his young life the spy had bound himself up in too many lies to ever hold himself to his word. Let Diluc satisfy himself with the stinging of his own right hand. If he had to prove himself, here and now, it had to be like this.
Not because he was sure of his own desire—he’d gotten too good at lying with his body to trust even that.
But he trusted Diluc’s naked honesty. And he knew he would kill a hundred times over to have Diluc look at him the way he did then, when Kaeya finally had them both in hand. As if the Khaenri’ahn were more than an actor playing out his part. For that faith, Kaeya would believe it.
No... it was the only way he could believe it.
Slowly, torturously, he stroked them both from base to tip. Kaeya kept his eye on the face of the redhead beneath him. He’d never hungered for anything so much as to see Diluc thus transfixed—and by what, in the end? An outcast. A liar.
His sworn brother.
“I wasn’t lying earlier,” the Khaenri’ahn said lowly. “Just say the word, Luc, and you can have my sword, my life—my body. I’m yours. So... how would you have me?”
“...In me.”
At some point, Diluc had lost the ribbon from his hair. A halo of wildfire spilled about his shoulders where he sprawled upon the rug. His eyes were half-lidded, his skin flushed with unfledged lust.
Was that it, then—lust?
Diluc wouldn’t really entrust his body to him like that, would he?
Frozen atop him as he was, Kaeya felt the warmth of Diluc’s hand close over his wrist. Squeeze, haltingly. “Kaeya. I want... I want to feel you in me.”
Do you, really?
Perhaps his influence was finally rubbing off on the other man. Here Diluc had had the audacity to lie to his face—and for a moment, Kaeya had wanted to believe him.
The Khaenri’ahn threw back his head and laughed.
The next thing he knew, it was his turn to be breathless on his back. Diluc had tackled him to the rug. Even in his naked vulnerability, Kaeya would be a fool to forget that his foster brother was in training to be a knight. He certainly had the coiled muscle to prove it.
“You’re an ass,” Diluc hissed. The redhead’s face was burning now, and how wondrously so. “You said I could have your body, didn’t you? If you meant it, then cut the glib talk and fuck me, Kaeya. And if you didn’t...”
He’d paused to draw a ragged breath. Or perhaps to punch him. Kaeya felt the weight of Diluc’s bandaged fist trembling against his shoulder. ...Thicker than water.
He reached up to cover the redhead’s hand. “I meant it,” he amended, quietly. “I’m sorry. I shouldn’t have laughed. You took me by surprise is all.”
Yes. Surprise. That was what he felt with Diluc straddling his stomach, glowering at him with that misguided storm of emotion in his eyes. For a moment, Kaeya could almost convince himself.
But if his lips and his wanton loins were mere liars, then his heart throbbed with the truth.
He sat up, pushing Diluc off his lap before he might delude himself into thinking he could ever deserve such raw intimacy. What could he say or do now that wouldn’t betray the baseness of his true nature?
He touched his sworn brother’s cheek.
“...I need to get something. Hold tight for me, Luc.”
*
I want to try something. Something I read about a while ago.
Diluc would be lying if he claimed he’d only had the glory of the past in mind when he’d uttered those words.
For too long he had been trying to imagine what it would feel like. It had been his torment on sweltering summer nights, when his chronic insomnia proved in full form. So too had it been a curiosity he’d indulged, once or twice, in the secrecy of the bath. But even the hot shame of probing his own fingers there could not have prepared him for his first experience of penetration.
Kaeya steadied his left hand against the redhead’s right hip, his fingers slick with the pilfered oil with which he’d prepared them both. It was an uncharacteristically gentle touch, and it drew Diluc out of his distracted rumination.
“Stop me if this is too deep,” the other man prompted.
Diluc sank his teeth into the knot of bandages around his right knuckles. No. He knew he wouldn’t stop Kaeya from easing into him then, not even as his lower body seized up with objection.
He needed an answer to the question that had tortured him for so long. If he let himself plumb the depths of his own depravity tonight, perhaps he’d finally understand why Kaeya could stir these urges within him, and only Kaeya ever had.
He had searched for those same sparks whenever he’d looked at someone else. Had endured the endless parade of powdered-up noble daughters trotted past his nose. He was his father’s sole heir: someday, Diluc knew, he would be expected to marry, to beget a son of his own.
Try as he might, though, he couldn’t bring himself to want a woman. Not the way he wanted his sworn brother tonight. Once the initial shock of pain began to subside, Diluc realized why:
Only Kaeya completed him.
Warmth teased his left ear as the other man leaned over him. Leaned into him. “How are we doing?” Kaeya prodded.
“Mm.” Distantly, Diluc remembered his mouth was full of fabric. He dislodged his bandaged fist. No matter how much it hurt, he had to know. “Go deeper.”
Kaeya’s answering laugh was fire against his skin. “Hate to break it to you, Luc, but you left your broadsword down at the training ground.”
He checked the redhead’s knees from slipping off his shoulders, since they were both starting to sweat in the summer night air. Then he kissed the hot skin below Diluc’s ear.
“Perhaps my humble sword can be of service all the same,” he murmured. “Do I have your leave to try?”
If Diluc hadn’t been in such a compromising position, he would’ve punched this ass for having the gall to mock him. He settled for anchoring his fingernails to the other man’s shoulders. “By the gods, Kaeya, if you don’t shut up—”
“I’ll take that as a yes.” Kaeya hoisted the redhead’s hips off the rug to afford himself a better angle, and...
It was a strange, almost surreal experience that followed, in Diluc’s mind. A part of him knew that he was as vulnerable as he had ever been then, naked on his back upon his bedroom floor. Another part of him registered a steadily dulling pain, the fullness of his sworn brother inside of him.
But for all he knew, the body in Kaeya’s hands might have been a stranger’s.
He had never moved like this. He had never wanted to move like this—not until oil-coated fingers were gripping his buttocks, and Kaeya’s fringe tickling his skin as the young man ducked to minister to his chest. It had to be a stranger who arched his back beneath him; who moaned, open-mouthed and unabashedly inflamed, until Kaeya came up to kiss him silent.
I’m yours. Those words had been on Kaeya’s lips, but Diluc recognized them as a lie. Precisely when or how the other man had come to know his body, far better than he dared to know himself, the redhead could only guess. Still, in that moment, as Diluc suspected he always had, Kaeya effortlessly turned him into his own plaything.
And he willingly surrendered.
Blood is thicker than water. Seed ran thicker than both, smearing his own stomach, and Kaeya’s. Diluc realized, hazily, that he didn’t care. Neither did Kaeya, judging by the way he buried his face in the side of the redhead’s throat and drove him harder. The stinging clamp of his teeth muffled a sound that Diluc had never heard him utter before. Raw, uninhibited release.
And he knew he had found his answer.
*
A heartbeat or an eternity later, Kaeya clambered off of him. As the other man hobbled away Diluc turned his head, and he only barely caught himself from calling after him.
But if he had imagined that an exchange of what was thicker than water would have left him with more than cooling shame on the floor, maybe he was the stupid ass.
Or maybe...
Footsteps neared his head. Kaeya tossed a towel at the sticky mess coating the redhead’s stomach. Then he sat cross-legged beside him and unwound the shredded bandages from his right hand. The bleeding had stopped, but Diluc’s palm still stung when his sworn brother rubbed in the healing salve.
...Stupid ass.
Kaeya kept his head bowed over his task. “I told you,” he said quietly, “I’m yours. If this isn’t what you wanted—”
He must have misinterpreted the grimace that was pricking tears at the redhead’s eyes. Diluc sat up with a huff.
“What part of this makes you think that you—that this isn’t what I want?”
A rough hand caught his face. It was Kaeya’s right hand, and the roughness the bandages that scraped his cheek. “None of it,” Kaeya admitted. “That’s why I’m scared to believe it.”
Such an unexpected confession left Diluc dumb. He had sometimes thought that the world flowed over Kaeya like water, leaving the young man unmarked and unmoved. He had never imagined his sworn brother to fear anything within its mortal bounds—least of all him.
Had he not been forthright enough...?
Meanwhile Kaeya traced his fingertips down the side of the redhead’s face. Diluc hadn’t realized his own lips were swollen until the other man touched them: he moaned with halfhearted protest.
Kaeya resurfaced with a sudden grin. “I didn’t dare to think you’d ever let me have you like this, you know. Now it’s all I can think about.”
Kaeya’s smirk alone could stoke a fire in the pit of his stomach, and Diluc no longer cared if the other man knew. Between them, there was no shame in honesty.
“Then have me again,” he told Kaeya. “Give me your body’s oath a hundred times. A thousand times.”
I want to feel you in me. I want to be the one thing in this world that can move you to delirium.
Kaeya chuckled. “You may have slightly overestimated my stamina. ...Still, I wouldn’t mind hearing you say it again.”
Diluc blinked at that. “What? The old oath?”
“Nothing so shallow as that.” Kaeya indulged him with another grin. “For all you scorn my ‘glib talk’, you do have quite the way with words, yourself.”
The redhead opened his mouth to object, then closed it again, aware that his face was burning. Nothing so shallow... Gods, he really had set aside his dignity in pursuit of answers tonight.
Still, he had found what he’d been looking for, hadn’t he?
He looked away from Kaeya’s smirk. Stiffly, he said, “I’m not going to say it again.”
“Mm.” Kaeya didn’t sound convinced. He touched the exposed side of the redhead’s throat; a thoughtful look darkened his eye. “Seems I left a mark. I’ll try to be gentler the next time you jump me and demand I fuck you.”
There was no shame in honesty between them, so Diluc felt none for punching him.
He knew Kaeya would catch his true meaning, anyway.