When Kaeya turned eight, he celebrated his birthday for the first time.
He always knew when it was, of course, a small tingle in the back of his head whenever the last day of November came. He knew that birthdays were special and some kids got cake and presents and lots of hugs on their special day.
In Khaenri'ah, birthdays were different. They were a reminder of the reason he was born, the sole purpose behind his existence. For his sixth birthday, his father gave him a knife and showed him how to use it.
He went to sleep that birthday with scratches and bruises all over his arms and a heart burdened heavy with responsibility.
Two years later, when Kaeya turned eight, he woke up in Mondstadt burrowed in a comfortable blanket with the warm sunlight shining onto his face. Oh, he thought quietly to himself, I'm eight now.
And then he put his birthday out of his mind and crawled out of bed to get dressed.
After he finished washing his face, he headed down to the dining room. Diluc was already there, his tiny legs swinging animatedly as he talked to Crepus, but he beamed widely when he saw Kaeya coming down the stairs. "Kaeya!"
"Hello," Kaeya said, still not used to the unconditional love the Ragnvindr family showered him with every day. Crepus smiled gently at him as he bowed slightly, sliding into the seat next to Diluc. "Thank you for the food."
Diluc was fidgeting a lot, his hands tucked suspiciously in his pockets. Kaeya blinked at him. "Diluc? Are you alright?"
Diluc bobbed his head eagerly. "Kaeya," he whispered loudly, a bright smile on his face. "I have something for you."
Kaeya stared at him. "For me?"
Crepus let out a sigh. "Diluc, I thought we agreed to do this after breakfast."
"I changed my mind!" Diluc said, and then he's reaching into his pocket and holding out something for Kaeya to take. "Here! I made it for you. Happy birthday, Kaeya!"
Kaeya took it tentatively with both hands, staring down at the little creation. It appeared to be some kind of bird sculpted out of clay. The wings were deformed, its face pinched and its legs too big in proportion to the rest of its body.
"Sorry," Diluc said nervously after a couple minutes of silence. "Maybe I should've just bought something."
He reached to take the clay sculpture back and Kaeya scrambled backwards. "No!" he said a little too loudly, clutching the bird against his chest. "No, I love it. I love it a lot! Thank you, Diluc."
Diluc beamed. "You mean it?"
"Yeah," Kaeya said honestly, looking down in wonder at the clay sculpture. "No one has ever given me something like this before."
Diluc leaned over and clutched Kaeya's hands between his own. "I'll do this every year," he declared. "Everyone deserves to have a happy birthday, especially you Kaeya!"
"Thanks," he said softly, and if Diluc could hear how shaky his voice was, he didn't comment on it.
"Alright boys, let's eat before the food gets cold," Crepus said. Diluc retreated back into his own seat, and Kaeya's hands suddenly felt so cold without his. "Happy birthday, Kaeya."
Kaeya straightened up in his seat. "Thank you."
"I don't have anything as amazing as what Diluc made." Diluc stuck his tongue out. "But why don't I let you try some wine during dinner? The bottle you're always staring at?"
Kaeya blinked. "But I thought I had to be an adult to drink that."
"Well, a little bit never hurt anyone. Besides, you turned eight today." Crepus reached over and ruffled Kaeya's hair. It felt so much different compared to his father's desperate hands, grabbing him roughly by the shoulders and pleading for him to finish the mission. You are our last hope, Kaeya. "I think that's something worth celebrating, no?"
Kaeya, you were born to save us.
"Okay," he said, the smile coming much easier than it ever did in Khaenri'ah.
And then, with the excited chatters of Diluc and Crepus filling the dining room, the small clay bird clutched tightly in his hand and the promises of wine and more fun times ahead in the day, Kaeya Alberich turned eight.
When Kaeya turned eighteen, he stopped celebrating his birthday.
The room the Knights of Favonius gave him was by no means terrible, but he had made no effort to turn it into home. Aside from the clothing arranged in the wardrobe and the basic necessities scattered in the bathroom, the room looked no more lived in than when he first arrived.
The moonlight shined through the open window, casting a glow onto the covers in front of him. He sat in bed, a glass of wine in his hands as he stared at the night sky almost wistfully.
He remembered when he was a kid, he couldn't wait to grow up, couldn't wait to become knights with Diluc and protect Mondstadt alongside him and try that fancy wine Crepus always liked.
But now, he wished he could turn back time. He wished he could go back to that naive and innocent child who only thought about catching up with Diluc as they played in the forest. He wished he never learned how to lie, and lie, and lie, until he stopped being able to remember when the last time he smiled for real was.
He wished he never found out how bitter this wine tasted.
Kaeya sighed, taking another sip. The day had passed by uneventfully. He hadn't told anyone about his birthday, and so the day had proceeded as usual, with Jean giving him various duties around the city. It proceeded as usual, with several meetings with treasure hunters and other pesky bandits taking up much of his schedule.
It proceeded as usual, with a Diluc-shaped absence that was becoming more and more painful as the days went on.
He hadn't seen Diluc since that day, when the rain turned red with Crepus' blood, when he had laid his whole heart bare and placed all his vulnerabilities into Diluc's hands as his lips mouthed the truth of his darkest secret.
He hadn't seen Diluc since that day, when the boy he grew up with pointed his sword at him and cut down the decade of trust between them.
"You liar," Kaeya said wryly. "You said you would always protect me."
His head hit the wall behind him with a thud, the cooling winter air brushing against his face. It had been many months since then, many months since Diluc disappeared from Mondstadt and took a large part of Kaeya's heart with him.
Kaeya wished he thought to bring the clay bird with him. But even that was gone, left behind in a house he could never return to.
You must carry out your mission, his father's voice echoed in his mind. Kaeya had forgotten so much over the years, but that voice had never left him. Kaeya, you are our dream.
Kaeya took another long sip of his wine. It burned all the way down.
"Hey Diluc," Kaeya said quietly. "I wonder where you are now. Inazuma? Snezhnaya? There's no way you're dead. You're too strong for that.”
“Jean has taken over your position," he continued. "It's not as fun without you here. I always thought I'd be by your side when you became the Grand Master. But I guess that wasn't in the cards, huh?
Hey Diluc, his mind whispered. Do you hate me?
Hey Diluc, his mind mumbled. If I was someone else, would you still have left?
Hey Diluc, his mind laughed. Why am I still alive?
"Happy birthday to me," Kaeya murmured to himself, finishing the rest of the bottle in one swing, the brightness of the full moon his only companion on that lonely winter night.
Kaeya blinks out from his memories with a jolt as the familiar scenery of Mondstadt falls into place around him. It's the evening now, the sun beginning its descent behind the buildings as the street lamps in the city blink to life.
He sighs; he hasn't fallen back into his memories in a long time. He knows he’s not who he was when he was eight, a hopeful and naive little boy who still believed that he could fight against his fate. He knows he's not who he was when he was eighteen, a young man who stood near the door every night just in case Diluc came home.
He turns twenty five today, and he feels like he's aged decades in just the past five years.
He's been wandering around aimlessly for awhile, and he smiles a little wryly when he sees where his feet have taken him. The sign for Angel's Share stares down at him from above, the lights blinking on inside the store as customers slowly trickle in after a long day of work.
Maybe I haven't grown up as much as I thought, Kaeya sighs, but pushes the door to the tavern open anyway.
Once inside, his eyes instantly scan around for the familiar spot of red. His heart drops slightly when it's Charles, not Diluc, who smiles back at him from behind the bar. But what did he expect? It's not like he expected Diluc to remember his birthday, and the last time he celebrated with anyone other than his own wine glass, Crepus had still been alive.
"Sir Kaeya!" Charles greets as Kaeya slides into a barstool in front of him. "How are you doing today?"
Terrible, his mind supplies. "Pretty good," he says, putting on his best public smile. It's charming enough to fool most people he's met, and the one person who used to be able to see through it is long gone. "Didn't expect to see you here today."
"Yeah, I wasn't expecting to be here either," Charles admits. "It was my day off, but Master Diluc begged off last minute. Said something about needing to check something out and asked me to take his shift for him."
There's a sharp pain that stabs Kaeya's heart and he shrugs it off. Diluc's life does not revolve around him, especially now that they barely acknowledge each other's presence, and there are plenty of other things Diluc could be doing other than trying to avoid Kaeya on his birthday. Even if the timing is a little suspicious.
"Oh? Interesting," is all he says.
He grabs for the glass when Charles slides it over to him. He stares down at his own reflection, the mask of a liar peering back up at him as it grins mockingly. It's been seven birthdays since he and Diluc parted ways, and he's developed a certain tradition of drinking glass after glass until he can barely walk.
He gives a different answer anytime anyone asks for his birthday, so he's not surprised that no one has brought it up with him today. Yet, sitting at the bar with the chattering of drunk friends and loved ones filling the tavern around him, he can't help but feel incredibly lonely.
The door slams open.
"Kaeya!" someone yells, and Kaeya jolts out of his stupor and turns around. That voice sounded suspiciously like—no, it couldn't be.
He sees a flash of red before a small body barrels into his stomach.
"Oof," Kaeya says, barely avoiding toppling out of the barstool. Small arms wrap around his waist tightly, red hair spilling out of the ponytail, and Kaeya's heart almost stops.
He's talked his way out of all types of situations. From placating international disputes to buttering up his informants, he's always had a quick response to everything.
But for once, Kaeya is speechless.
"Happy birthday!" the boy says, pulling back with a huge grin. Kaeya would recognize that face anywhere, from the puffy cheeks to the slightly crooked teeth to the sparkling bright eyes. It's been more than a decade since he last saw this, but he would never forget the happiest times of his life. "I told them it was your birthday but no one believed me! I would never get the date wrong. It's your special day after all—"
The boy cuts off, eyes widening almost comically as he stumbles back. He barely reaches the height of Kaeya's stomach. "Wait," says eight year old Diluc. "You're not Kaeya."