And I would do anything for you (anything at all)

Chapter 1 (Childhood)

Kaeya is eleven years old when Crepus accepts him into the Ragnvindr household, two and a half years older than the man's biological son. Diluc, all cheery smiles and bushy, shoulder length hair - excitable as a puppy. As clingy as one too; it takes about one week for him to practically move himself into Kaeya's bedroom.

That's bad. If he sees Kaeya crying over the last shred of his father he has left, a half burnt up letter not even addressed to Kaeya himself, it would be suspicious. He has to wait for Diluc to pass out on his shoulder before bringing it out, because for all his childishness his new brother might still be smart enough to put the pieces together.

"Do you want my pancakes?" Diluc asks, after Kaeya has been scraping his breakfast around his plate for the last twenty minutes.

"No. I'm fine, you should start eating."

He pouts like he's worried, but if he doesn't finish his own food soon he'll have to go to training hungry. Master Crepus is not the type to go easy on his son - Kaeya can at least relate to that.

"But it's impolite to start eating before everyone is ready."

"Is that a Mondstadt custom?"

Diluc stares at him, "You're not from Mondstadt?"

He can't reply to that honestly, "I don't know where I'm from; we always travelled when I was younger."

"Oh..." he frowns, tapping his fork against the side of his plate - it's an annoying racket, "Father and I have travelled around too. He took me to Liyue Harbour to see the boats."

Crepus definitely didn't just want his son to see the boats - it was probably to introduce him to the trading routes for the Dawn Winery. Kaeya's father already gave him the briefing on their family's international business, from Mondstadt to Snezhnaya, with subsidiaries in Inazuma.

'Impress him, son. Ingratiate yourself to their family and their business.'

The maids come and escort Diluc outside for training, and Kaeya follows behind. Crepus welcomes him to the gardens as well as his son, throwing a wooden sword over. Diluc gets a silver one with a feathered Favonius hilt -

"Were you a Knight of Favonius?" He asks, to flatter him.

Crepus laughs, "Ah no, I wish... I never managed to pass the knight's exam." He looks down to Diluc, who's holding up his sword with two steady arms, "I think Diluc has a promising future with them, though. So long as he receives a vision soon."

"I will, father."

"Are you interested in becoming a Knight too?" Crepus questions, turning back to Kaeya.

Yes, though not for the right reasons. "Of course... I would love to pay this city back, somehow, for taking me in so kindly."

He ruffles Kaeya's hair and commences training, bringing out a few hilichurlian training dummies for him to go at. Crepus directs Kaeya a little bit - hold the sword higher, keep his stance steady - but it's gentle, kindly. Much sweeter than how his own father trained him, with rough words and, when necessary, rougher blows.

That warmth is why Kaeya just grits his teeth when Crepus moves onto Diluc, bringing out his own sword and beginning to duel him. Despite never having passed the knight's exam, Crepus is still a grown adult and Diluc is just a snotty little kid. He probably could pass the exam now, but has chosen to focus on his son's training instead.

It doesn't look like he's holding back. Just over the last week, Diluc has gone to bed every night with countless scrapes and bruises from being thrown around all morning. It seems he gives as good as he gets though, as Diluc manages to land a gash upon Crepus' cheek before having his legs swept out from underneath him.