Family? Bull shit. If Kaeya believed in family, he’d still be there for Diluc. He would have stayed, he wouldn’t have left Diluc alone and he wouldn’t have become an alcoholic brat with a penchant for manipulative tactics and violence. If Kaeya cared about family, perhaps father would still be here, in memory at least. Perhaps their memories wouldn’t be moments of fleeting past long gone, and just a few of the many things they'd do together. But no, Kaeya left, with a sick smile on his face and cryo vision in hand on that fateful day. And Diluc despised him. He hated him.
At least, that’s what Diluc told himself as he followed Kaeya, the bastard was true to his word and a few nights later he heard that Kaeya was taking a temporary leave from the knights and saw him slip through the gates under the cover of darkness. Well, two could play that game, Diluc was the city’s vigilante protector. Slipping under the cover of night was his specialty.
He didn’t expect Kaeya to head to the beach, then to musk reef, walking across an ocean with ice freezing under his boots, melting just as quickly. Luckily, Diluc knew a better way to get there, albeit it was a bit dangerous. The traveler had told him of a portal on a nearby cliff that could be reached via a glider and wind current. Why it even worked he had no idea, but here he was, hiding behind some rocks while Kaeya walked onto the shore. Diluc didn’t expect there to be a giant gateway in a small, shallow pool in the middle of the little island, but there was, and Kaeya seemed to be walking towards it.
“You’re rather sloppy for a vigilante” Kaeya remarked.
“Oh look he caught me” Diluc said sarcastically, coming out of hiding. “Now what the hell are you doing?"
Kaeya didn’t pay him any mind and examined the runes all over the gateway "Nothing of a young nobleman’s concern. Go, run back to your tavern and your mansion, you wouldn’t understand a poor bastard like myself” his tone was mocking, yet still a bit sharp. He was at least a little angry. Well at least he wasn’t lying anymore.
“Kaeya"
"I’m going home"
Diluc scoffed "What, did you live a pitiful life here? Did you swim all the way to Mondstadt before father found you?"
Kaeya ignored him and wiped some dust off the old gateway "This is the last time you’re ever going to see me and that’s all you can say?"
He stood up straight and held up a hand in front of the gateway "Impios et deserta, fugiendum, et proiecit, aperi portas tuas ad me” he chanted.
Diluc was about to ask him just what the fuck he had said when suddenly a blue low lit up the little island, a portal opened in the gateway. “What the-?"
"Well this is goodbye, Diluc” Kaeya said, walking up the steps of the portal.
No.
Some part of Diluc didn’t want to see him go for whatever reason. He wanted Kaeya to stay.
“Kaeya!"
He had already gone through, Diluc desperately sprinted up the steps, throwing himself into the portal.
"Kaeya!"
Light blue eyes looked down at the little boy, a hand moving up to rub the sleep out of his eye "Mmm Diluc? What are you doing? It’s long past bedtime…"
The redhead didn’t answer and hugged the taller boy, face getting smothered in a loose fitting linen shirt. Kaeya sighed as sobs racked his little brother’s body, patting his back. "Did you have a nightmare again, Luc?” he asked.
Diluc looked up and nodded, sniffing as tears fell from bug red eyes. “Come on” Diluc followed Kaeya into his room, crawling on top of the bed.
“Do you want to talk about it?” Kaeya asked, sitting down next to him.
Diluc looked down and fiddled with the long sleeves of his shirt “I saw the bad guys that pops was talking to earlier. They were all beating you up, and those terrible things about you again! It was scary, there was blood everywhere, and they ripped out your eye-"
Kaeya stopped the younger boy, not wanting to hear much more. What a morbid dream for a child "Diluc, it’s ok"
"No it’s not!” Diluc snapped “Those guys were saying nasty stuff about you even after dad told them off! They kept calling you a bastard and a peasant! But you’re none of those things and it’s just wrong!”
Kaeya chuckled and patted Diluc’s head “Ok, ok. It’s alight. Those bad guys aren’t going to come back anytime soon. Now for the love of the archons, please go to sleep Diluc"
Diluc pouted and wiped away his tears, snuggling into the bed with Kaeya. With his hand in his big brother’s, no one could hurt him, no nightmares would come. Big brother was his knight that would fight off the monsters.
"Oh goody you’re awake” Diluc groaned and sat up. He felt so sick.
“What the fuck…?"
He hadn’t had a dream since father died. Even then, they were usually just the usual nonsensical dreams everyone had. He gritted his teeth at the memory of that night. Diluc had woken up from a nightmare and ran straight to Kaeya’s room. He missed the Kaeya in that memory. That Kaeya at least had the common sense to lie to an naive child instead of shattering his entre world with a few sentences.
"If you’re wondering what happened, you decided to follow me here, proceeded to throw up, and then pass out. If anything, your current predicament is your fault” Kaeya scoffed, crossing his arms.
“Why did I pass out though?"
Kaeya sighed "I guess it’s the strain that the portal put on you. Traveling in between different planes of existence requires for your body to change a bit. It get’s better after your first time"
"Different planes of existence?” Diluc repeated, looking up at Kaeya who was sitting on a fallen tree. They were in a normal enough place that could literally be anywhere in Mondstadt. The red head got up and brushed himself off, adjusting his gloves and making sure he still had his claymore strapped to his back.
Kaeya got up and moved a tree branch aside, revealing the valley that was spread out before them, with what looked like a large walled off city in the distance. “Welcome to Kaenr'iah. The godless city”
.
.
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Author’s notes
For reference, Kaenr’iah (in this story anyways) is roughly the same size as Ba Sing Se from Avatar if you want a sense of scale. As for cultural inspiration, lost of stuff I’ve found has suggested Southeast Asia so I will be taking elements from more than one country as we have no information as of now.