JEAN

Jean shuffled the papers together again with a sigh and stacked them in a corner of her desk. The Knights were still no closer to finding out the true identity of the Darknight Hero. Thus far said mysterious person had only been a help to the city, catching a few petty criminals and clearing out monster camps close to the city. It was tempting to just continue to let them be, but with little evidence to identify them it could quickly become a problem if they decided to turn against Mondstadt for any reason. Especially considering how they always seemed to be a step ahead of the Knights, not to mention a bit embarrassing when they would show up to the scene of a crime to have the perpetrator already caught and hanging from the statue in the square or bound and left in front of the Knights of Favonius headquarters.

After several incidents reported little more than "a dark clothed figure and flash of red," Jean had assigned Kaeya to head the investigation. His methods were often unorthodox, but effective. Despite the carefree, lazy persona he portrayed, Kaeya was actually a very dependable knight. Although, come to think of it, she hadn't seen him all day. It was late in the evening and she began to wonder if she should worry about his uncharacteristic absence, when she realized the date. April 30. Typically Kaeya was a dependable knight, today was the exception. He had consistently failed to show up for work on this particular day for the last several years. It wasn't a happy day though - Diluc's birthday had become the anniversary of Crepus' death, as well as around the time Diluc had left Mondstadt. While she wasn't privy to the details, she was pretty sure Kaeya and Diluc hadn't been on the best of terms at the time, and other than a couple letters that had claimed he was "traveling" they hadn't heard from him in quite some time.

Whether trying to surround himself in familiar or drink away the memories of the past, Kaeya could typically be found on this occasion at the Angel's Share Tavern. Jean decided she would stop in briefly on her way home, just to make sure he was okay. Undoubtedly, he would return tomorrow like nothing ever happened, but still it couldn't hurt to check.


4 Years Ago

DILUC

"Let's get going, Diluc. We should head back home before it starts raining, don't you think?"

Congratulations and invitations to drink continued to circle around the room. While grateful for the celebration, Diluc was more than ready to head back to the calm of the winery. "Yes Father," he agreed and went to join the wagon and horse they had prepared for their journey home.

Shortly after they were on the road, Diluc heard bits of his father's conversion, half to himself and half to his son.

"I wanted to become a knight too when I was your age. However I wasn't fit for the job, and the gods also had other plans for me. But you have succeeded where I failed. The Knights of Favonius are lucky to count someone as brilliant as you among their ranks."

"You contribute to Mondstadt as much as the knights, just in a different way," Diluc replied.

"Haha, you're right," Crepus returned, though he didn't sound like he completely believed it himself. "Still, I'm proud of you, son."

Hearing those words was his greatest motivation, still, he realized too late, he should have been paying more attention to his immediate surroundings rather than the conversation.

The darkening sky grew more ominous as hilichurls appeared from the nearby woods. Other members of the transport attempted to drive them off, but their numbers continued increasing until the transport was forced to come to a complete halt. An eerie howl filled the air, and a terrifyingly large monster appeared.

Diluc retrieved his claymore and moved to join the fight. Despite being the only vision wielder and trained knight of the group, it was quickly obvious the dragon was still far more than he could handle on his own. He had failed to make even a single meaningful hit against the winged beast before getting hit himself and flung back into the wagon. "If only I was stronger…" Crepus appeared from within the covered wagon and faced the dragon.

"Father."

Steeled in his determination, the older man extended a hand and black fiery chains appeared, binding Ursa the Drake.

"That power… how…"

The drake roared and struggled against its chains as they tightened around it.

"Great job," Diluc praised in disbelief, " you managed to defeat it. Now we-"

As abruptly as Ursa had been bound, the beast shrugged off the bindings and plodded away, just as Crepus crumpled and fell to the ground with a thud, clutching at his chest as he cried out in agony.

"We came to help. Is everyone alright?" Kaeya and a group of knights called in the distance, but the sound was barely perceptible to Diluc as the life in his father's bloodied form faded before him.


KAEYA

If Khaenriah and Mondstadt went to war, which side should he support? His birth father who had mercilessly abandoned him, or his adoptive father who had loved and raised him? For the longest time, Kaeya had agonized over these impossible questions, caught between the opposing demands of loyalty and duty, faced with an impossible choice between truth and happiness.

Crepus' death upset this delicate balance. He was freed of one obligation, but also ashamed of how selfish he was being. He was unable to save Crepus, arriving moments too late. As a brother, he should have shared in Diluc's grief, yet as their father lay dying, he hung back.

Perhaps that was why he found himself now outside Dawn Winery, drenched in the pouring rain and knocking on the door. He still hadn't quite figured out how to articulate it, but Diluc had always been his sounding board, perhaps he could sort through the chaos in his mind.

He wasn't sure his knocking could be heard over the raging storm, until finally the door slowly opened, Diluc himself behind it.

"'Luc."

Diluc wore an impassive expression on his face, having forgone the coat, but still wearing the blood stained clothing from earlier. Their father's blood. Exhaustion was apparent, yet he looked to be making no effort to rest, instead blankly standing in the doorway, neither inviting Kaeya in, nor purposefully keeping him out.

"I wanted to talk," Kaeya began, now having second thoughts. Crepus' death would surely take a massive toll on Diluc, perhaps now was not the time to burden him with his own troubles as well.

"Then talk." He looked absolutely wrung out. "I doubt I will have much to add, however."

"I'm sorry. I'm sorry I wasn't there in time to help - to save…"

Already numb to the meaningless rambling and what ifs he had received all evening, Diluc turned back toward the table covered with a myriad of his father's paperwork detailing travel routes, business plans, invoices, and the like, periodically reordering them or making some small note as he sought to make sense of them and establish a history.

Was Diluc even listening? Kaeya had thought he would be distraught, was he already planning business changes before a funeral could be prepared?

"Do you remember any strange visitors or secret trips father might have taken?" Diluc asked, interrupting Kaeya's rambling.

"Do I- What are you talking about?" Kaeya asked, confused at this seemingly unrelated line of inquiry.

"Strange people he might have met, places he might have gone. That power… for someone who doesn't hold a vision…"

"Aside from a certain child that just happened to show up at his door?" Kaeya asked self-depreciatingly.

"Taking in a lost kid in the middle of a storm, more an act of kindness. I was thinking something more…"

"I wasn't lost."

Diluc finally looked at him with vague interest.

"Your father went to get some grape juice and never returned." He flipped through more papers in his hands. "Did he ever actually make it to the winery? It's not like it's far from where you were found."

"He wasn't getting juice." Keaya deadpanned. "He left me."

It must seem that way to a child. Yet, somehow Diluc didn't get the impression Kaeya was dramatizing at the moment. "He left you?"

Kaeya nodded. It was too late to turn back now. "He abandoned me here, knowing Crepus would take me in. I was supposed to assimilate into Mondstadt, to gain a position, in case it was needed later."

"Later?"

" I was sent here as an agent of Khaenri'ah."

There was more life in Diluc's eyes than Kaeya had seen all evening, but it was obvious it was a barely controlled storm.

"It was all a lie."

"Based on a lie," Kaeya admitted, "but just the one. Our childhood wasn't a lie. Crepus really was a better father figure, you inspired me to join the knights…"

"Your gained position," Diluc seethed. "To turn against us? To turn against Mondstadt?"

"It may never come to that," Kaeya backpedaled. "Even if it did, I don't know that I would side with Khaenri'ah now. So much has happened, changed. And honestly, who leaves a kid to do their dirty work like this?"

He continued to reason with his adoptive brother, but it was clear Diluc was no longer listening, the tempest breaking free, a single word escaping his lips as he drew his sword.

"Traitor."

"'Luc, just listen to me," Kaeya pleaded. "It's not like that."

"Just lies. Stop lying to me."

Kaeya backed out the door he had only recently entered, searching for a way to calm his brother's fury, when the greatsword made its first strike.

He was forced to draw his own sword, parrying and dodging repeated attacks, without landing any of his own.

He had expected anger, though not to this extent, it was only fair. He had lied, deceived all those he counted as important to him, for years, and this was his punishment. He hadn't been able to save Crepus, hadn't been there to comfort Diluc, hadn't been a good brother. He deserved every bit of this.

In a proper duel, Diluc had him outmatched in power, though Kaeya was more nimble and quick. Perhaps he could evade Diluc's attack long enough to reason with him. Rather than tiring though, Diluc seemed to gain momentum. His last strike made contact, a searing hot blade cutting through cool skin. Kaeya continued to dodge as best as he could, gradually being backed toward the vineyard, receiving multitudinous wounds along the way.

"You win," he panted, stumbling over the rocky descent and landing on his backside.

Diluc had yet to spend all his wrath however, another hit sending Kaeya sprawling with a whimper.

It was his fault, Kaeya knew, his own doing. He deserved this. Deserved the stinging rain and sizzling wounds, the hatred and the pain. Deserved or not though, he realized it would soon all be over, as Diluc prepared for the final killing blow. Knowing it would be futile, he threw up his arms as a weak shield against the inferno of flames coming for him.

Suddenly a bitterly cold elemental energy coursed through him, an icy shield taking the majority of the hit as tongues of fire licked at his skin, fire and ice meeting in a dramatic clash.

The rain and ice soon extinguished Diluc's flames, his crimson eyes briefly meeting an azure, a multitude of emotions playing across his face - anger quickly fading as realized just how close he had coming to killing his adoptive brother, regret at his overreaction, and briefly like he would be sick, before the fervent redhead ducked his head in remorse, dropping his claymore and hastily disappeared into the night.

Kaeya lay on the ground, surrounded in scorched earth, amazed he was still alive. Telling Diluc the truth tonight had been a mistake; he wished he had never lied in the first place. Strangely his brother's fiery attack did little to dissuade him from Mondstadt however. That forthright passion and desire for justice was what had drawn him in, made him also want to join the Knights in the first place, to protect the city and people that had become home in a way Khaenriah never had been. His original goal of sorting through the chaos in his mind had been achieved, unfortunately now he was left with an even larger hole in his heart.

Gradually he got to his feet, every bone in his body aching, and limped forward a few steps. The city was a long walk from here and he needed to gather some things, and hopefully see a healer, before he was thrown out of the city should Diluc decide to share his secret.


DILUC

Kaeya had been long gone by the time Diluc returned to the scene of his fiery attack. Not that he could blame him, he thought, staring at the scorched ground. Kaeya now had a cryo vision, probably the only one that could have saved him from Diluc's murderous attack. He should be happy for his adoptive brother, in a way he was. He just wished it could have been any other way, if he hadn't nearly killed him before the gods recognized the blue haired boy. Still, he should be grateful they did, that Kaeya would live to hate him. The deception still stung, but he knew he had massively overreacted. Father wouldn't have been pleased to see his sons acting like this, fighting mere hours after his death. Once motivated by his father's praise, now it seemed to Diluc all he could now was disappoint.

"We would lose all credibility if the people found out the incident was dealt with by a mere businessman," the Inspector's words finally reached his consciousness as Diluc stood in the Knights of Favonius office, relaying the previous day's events and trying to keep his cool. "They won't trust us to protect them anymore."

"My father gave his life to save us all," Diluc reasoned. "We can't just pretend his sacrifice never happened."

"Fame and glory shall benefit the living. The dead have no use for them."

Diluc clenched his fists and bit his tongue, taking every ounce of his strength to not take out his anger on his superior officer.

"If your father was still alive, we would have welcomed him into our ranks, just like he dreamed of in his youth. Too bad he's no longer with us."

Not only were they trying to cover up his father's death and claim credit for defeating the beast, now they were mocking him directly. Diluc couldn't, wouldn't, be a part of this any more.

"Fine. Don't consider me a knight anymore then either." He ripped the pyro vision from his belt and slammed it on the desk in front of him. "Don't you dare forget that Mondstadt exists because of people like my father."

Turning around, he left the office without waiting to be dismissed, slamming the door shut behind him.

Eyes were on him as hastened down the halls and through the city, whispers following. He didn't care. He didn't understand. Why would his father want to be a part of that?

Putting as much space between him and the Knights headquarters as quickly as could, he walked through the gates and continued on, no particular goal in mind.

Father wished for a vision, to be a knight, an ambition he fulfilled only through his son, but he seemed so proud when Diluc had managed both at an early age, when Kaeya had also joined the Knights. What would he think now? His knighted son had failed to protect, nearly killed his brother, and left his vision and the Knights all within a day after his death, not exactly a record to be proud of.

Still, there was more to the story, he was sure of it. Father must not have known the extent of corruption within the Knights. And the attack on their transport seemed out of the ordinary as well. Sure, monsters periodically attacked travelers and merchants, but this was different - planned, premeditated. And where had he gotten that power? The black fire and chains that had so easily subdued Ursa the Drake before Crepus collapsed… he had to find out more. He had nothing left here, nothing to hold him back. He would avenge his father's death and get to the bottom of this mysterious power.


JEAN

Heading out for her regular patrol, young Knight Jean Gunnhildr walked along the outside of the city walls toward the bridge leading across Cider Lake. The area around her patrol had just been cleared by her Senior Diluc and Kaeya a few days ago, and it was unlikely any monsters had had the time to relocate back into the area. Still, she was determined to do something of use to keep the city safe.

Her thoughts getting ahead of her, she almost tripped over the errant leg that stuck out from its owner's half hidden position behind the bushes. She abruptly stopped to check on the citizen, only to find it was Sir Kaeya himself.

"K-Kaeya? Are you alright?"

He didn't immediately answer.

She stooped down and put a hand to his shoulder to gently shake him awake.

The blue haired knight recoiled away from her touch as if she had struck him. "I… I'm okay." he answered, despite his appearance saying he was anything but.

"Why?-" she noted the empty wine bottle and dirty uniform. "You'll be in trouble if you're found like this when you should be on duty… not to mention you aren't of age yet.."

"Surely the Knights can do without me for one day," he murmured without explanation.

She grabbed his hand, intending to help haul him to his feet, but he hastily pulled it back. Beginning to grow irritated, she reached for it again, stopping short as she realized it wasn't just dirty, but covered in dried blood.

"Kaeya, what happened?"

Taking a second look, she realized his typical gloves were missing, his palms burnt and bloodied. Several other cuts littered his clothing and forearms, and the strong smell of alcohol only somewhat masked the lingering smell of smoke. The only fully intact thing was a shining cyro vision hanging from his belt.

"Just leave me alone."

"You need a healer," she returned, somewhat gentler.

"I'll go." He painstakingly moved into a more upright position. "Just cover for me today. I'll be back tomorrow. Promise."

She looked at him again skeptically. He shouldn't be back on patrol tomorrow, not based on his current state. She still needed to finish her duties though, or all she would manage was getting them both in trouble.

"I just took on a little more than I bargained for. Finish your patrols today, and I'll be gone before you get back."

Finally Jean agreed with a sigh. "Alright, I'll go. But I will come back here on my way back, and if you're still here, my next stop will be to the Cathedral to find a healer, not the Knights of Favonius Headquarters."

Kaeya nodded slowly, still not quite meeting her eyes.

"Thank you."

Jean hurried through the usual route, intending to make up lost time and return before Kaeya could get himself into further trouble. As expected, there were no large camps of monsters, or even evidence of there having been one recently. Just what had Kaeya gotten himself into? He was a skilled swordsman and should have had backup before raiding any larger camps. Still….

True to his word, when she returned a few hours later Kaeya was nowhere to be seen.

Jean traveled through the city to the Knights headquarters to make her report and see what other duties she needed to fulfill for the day, but upon her arrival she found it in a quiet upheaval as well. Young knights gossipped in whispered tones, and none of the higher ranking knights appeared to be available, apparently in some meeting.

"What happened?" she asked.

After a minute of silence, another recent recruit answered. "No one really knows, but I heard the Cavalry Captain quit, and someone drove off an attack from Ursa the Drake."


KAEYA

After an interminably long walk back to the city, a necessary break, and brief run in with Jean, Kaeya dragged himself into the Church of Favonius Cathedral, seeking a healer. He now sat in the rear of the church after a prolonged healing session, looking for a chance to slip away unnoticed. He had intermittently dozed since his arrival here, but no one appeared to be looking for him to arrest. Was it too much to hope Diluc hadn't shared his secret? He had nowhere else to go. Whether toward imprisonment, exile, or distinguished career in the Knights, he didn't know, but the Knights of Favonius Headquarters was his next destination he decided.

"Did Mondstadt always have so many stairs?" Kaeya mumbled to himself as he ascended the final steps into the Headquarters building, body aching again. His time with the healer at the church had helped considerably, much more than his haphazard first aid with the few items he had borrowed from the tavern, but he still would have happily slept for a week straight. He had promised Jean he would return today, however, and he knew that if he didn't she wouldn't rest until she had found him and properly chewed him out.

He had no more than opened the doors and stepped into the hallway, before Jean was at his side and directing him out again, talking in hushed tones as she went.

"We've been assigned to work together," she explained, "Light duty while you recover from your injuries."

That earned him another skeptical look as she eyed his injuries again. He knew she didn't buy the lame excuse he had given before, but for now at least she didn't press the matter.

Instead, she guided him toward the plaza, away from the crowds.

"Captain Diluc has left the Knights," she informed him, "if you didn't already know."

"I did not," Kaeya returned, a slightly surprised look on his face.

She believed that much.

"He left this," she pressed a small wrapped package into his hands, "you should return it to him."

Peeling away a layer of paper, Kaeya recognized the warm glowing orb as his brother's pyro vision. Why had he left this behind though?

"Something is going on within the Knights," Jean added. "From all accounts, he seemed pretty upset when he left, but none of the commanding officers will give any details, just to carry on as usual until a new Calvary Captain is chosen. I know there's something they aren't telling us though. Do you have any ideas?"

"Not about the Knights," Kaeya answered truthfully. Diluc's departure may or may not have anything to do with him, but he wasn't about to offer that until it became pertinent. Diluc had no reason to leave on account of him that he could think of though, unless he just didn't want to see him anymore. As a higher ranking officer, not to mention knowledge of his past, Diluc wouldn't have had much trouble ridding the Knights of Kaeya's presence though, if he so chose. There had to be more to it than that.

Jean nodded succinctly. "I'll look into it more as I can. In the meantime, would you ask Diluc why he chose to leave so suddenly?"

Kaeya stiffened involuntarily. "I- I could. I don't know when I'll see him again though. I'll be staying in the Knight's barracks now. Dawn Winery really is too far to travel on a daily basis."

Never stopped him before, went unsaid.

Another suspicious look from Jean.

"He'll probably be at Angel's Share some time, or maybe I can find some time to visit the winery over a weekend."

Two weeks quickly went by and Kaeya had failed to spot Diluc at the tavern, wandering the city, or even getting groceries. As he now slipped into a back row of the Cathedral, he observed the well attended memorial ceremony for Crepus. Citizens and Knights filled the majority of the pews, as well as the staff from Dawn Winery were in attendance. The one particular redhead he had counted on seeing there was conspicuously absent however.

After the service, he sought out Adenlinde for answers. Whether she knew the extent of the brothers' fallout or not, she was never anything but kind and courteous to both.

"Is Diluc alright?" Kaeya asked, "I couldn't help but notice he isn't here."

Adenlinde seemed surprised he didn't already know. "Master Diluc is currently out of town. He had been for nearly two weeks."

Since their fight. Diluc had quit the Knights and left town within a day of their fight. It was definitely related.

"Do you know when he'll return?"

Adelinde shook her head, suddenly looking a little sad. "I'm afraid not. It may be quite some time. The tavern and winery business will continue as usual though, so no need to worry. And, of course, you are still welcome to come by."


PRESENT

Consciousness gradually returned in stages, a comfortably warm room, somewhat darkened, quiet save the occasional clink of glasses. Kaeya raised his head, unsure of when he had actually dozed off. Despite what he often led his acquaintances and informants to think, he did not often drink to the point of passing out. His gaze fell on the notes he had left on the table in front of him, the Darknight Hero case he was supposed to be investigating. Nothing that couldn't wait another day though.

Blinking away the fuzziness of sleep and too much drink, he saw his bottle had been replaced with a clear glass of water and a serving of the bitter herbal hangover remedy he remembered Adelinde made on occasion back home, at the winery, he mentally corrected. He missed it, her gentle attention to detail.

Even with Jean's help, eradicating the corrupt Inspector Eroch and his commiserators had taken much longer than he would have liked. Coupled with additional responsibilities as Calvary Captain, he had only spent a few days at Dawn Winery since Diluc had left nearly four years ago. Now, with Grandmaster Varka away on an expedition and the Knights as short handed as ever, he doubted excess free time was likely to come his way.

News about his brother's whereabouts was sparse, and often out of date by the time he received it. He had been to several nations, apparently working his way through the ranks of Fatui and leaving a trail of bodies in his wake. Kaeya tried not to worry, but as the red glow of his brother's vision on his nightstand seemed to grow fainter and fainter, he wondered if Diluc would ever make it home. The Fatui diplomats in Mondstadt weren't very forthcoming, but he had learned a little about Delusions, counterfeit visions made by the Fatui, and guessed that was where Crepus' power had come from when he defeated Ursa the drake. As witnessed, they were dangerous weapons however, and carried the risk of backfiring and ultimately killing their user. He understood Diluc wanted to know how and why his father had acquired such an item, but he now had every reason to believe Diluc was using that same weapon in his crusade against the Fatui. Poetic justice. But at what potential cost? It was tragic what had happened, but he just wanted his brother to come home. Diluc may not wish to call him brother anymore, may not want to be a part of the Knights, that would be too much to hope for. As long as he came back, that would be enough.

Kaeya spent another few minutes in contemplative silence, absently taking a sip of his Death After Noon, only to be reminded it had been replaced with water. Typically Charles would just cut him off, if it even came to that. He turned to voice his half-hearted complaint, but paused before the words could leave his mouth.

Across the room, a familiar silhouette was tidying glasses behind the counter. He paused almost imperceptibly, slightly favoring one side, as if from injuries that hadn't quite healed, a myriad of scars covering pale forearms where dark sleeves had been folded to his elbows. Lean figure clad in black, crimson hair tied into a high ponytail, he could be equally comforting or imposing, depending on where you stood. Diluc was back.

Taking a sip of the water left to him, a slight smirk traveled across Kaeya's face as he pieced together the picture in front of him. Four years away may have changed Diluc in some ways, physical scars and undoubtedly mental ones he couldn't see, but some things would never change, that need to protect, to strive for justice.

Knight or not, Diluc couldn't leave that part of his life.

Understandably, the chosen arrangement wasn't comfortable for the Knights, it wasn't convenient. There was reason behind the actions though, impulsive as they may have been at the time. It had taken quite a while for Kaeya and Jean to uproot Eroch and his accomplices and their treachery. The Fatui were still a constant thorn in their side. It would be difficult to suddenly fall in line again with the organization he felt betrayed by. Legality may be in question, but the motives were not.

Kaeya, of all people, could keep a secret though. He took another swallow of water and rest his head again, willing to act none the wiser. Eventually Diluc would want to go home and kick him out. Until then, he would relish in the fact his brother was finally home safe.

Welcome home Darknight Hero.