Chapter Text
Thunder sounds overhead and sheets of rain clatter on the roof of Mondstadt’s most popular tavern. Behind the counter, Diluc scowls — though not because of the weather. The affront in this case is the blue-haired Knight of Favonius who sits at the bar, a glass of wine held carelessly in one hand as he grins like a Cheshire cat at the unfortunate bartender.
“Now, now, Master Diluc, there’s no need to be so rude. I thought I’d be doing you a favour, what with the weather like this.” Kaeya waves a hand airily at the ceiling, as if to illustrate his point. “Or do you expect your informants to go out in a typhoon?”
“Get to the point, or get out,” Diluc growls in reply.
Kaeya sighs. “Very well. There have been... reports of a well-dressed gentleman with pale blue hair visiting various settlements around the place and asking if they’ve seen anything unusual in the sky.”
“And?”
“And, I have reason to believe this so-called gentleman is the Third Harbinger.”
“So why is he asking civilians about the sky?”
Kaeya goes quiet. He has his own suspicions, but he doesn’t especially want to share them. Least of all with Diluc, who is known for overreacting to– well, just about everything. More to the point, it reveals things about Kaeya that he has no interest in revealing. “Perhaps you can find that out for yourself,” he says, downing the rest of his glass and moving to leave.
Diluc grabs his arm, and only Kaeya’s exceptional self-control keeps him from flinching at the abrupt contact. “What aren’t you telling me?” he asks roughly, in that tone of his that makes it sound like he’s five seconds from summoning his claymore and separating someone’s head from their shoulders.
“That’s everything concrete that I know–” Kaeya begins, but he’s cut off before he can continue.
“What aren’t you telling me?”
“Fine, okay, so I have a suspicion that the Harbinger is in Mondstadt to find a certain someone...”
The redhead raises an eyebrow, and Kaeya notes vaguely how aggressive Diluc can make such a simple action seem.
“The Lost Archon,” the knight says reluctantly. “Do you know that legend?”
“Never heard of it.”
“Well,” Kaeya says, twisting his wrist free of Diluc’s grasp and stepping out of reach, “I think Lisa has a book on it, she’ll probably be able to explain much more... eloquently than me.” And with that, he turns and exits the tavern, skilfully freezing the rain that falls around him into an umbrella that shields him from the downpour. The door shuts behind him with a click, and the only evidence that he was ever there is the flurry of snowflakes falling to the floor.
///
The storm breaks two days later, and the very next morning, Diluc finds himself in the library of the Knights of Favonius headquarters, asking Lisa about the ‘Lost Archon’ that Kaeya mentioned that night.
Lisa raises an eyebrow and leans across her desk languidly. “I’m curious, Master Diluc,” she says with a smile that seems to spark static in the air, “where did you say you heard about this... Lost Archon again?”
“Kaeya,” he answers stonily, unwilling to admit that he actually listens to anything his former brother says.
The electric energy dissipates, and Lisa’s mysterious expression is temporarily replaced by a small frown, before she returns to her usual insincere smile. “Ah, of course. The Cavalry Captain truly does discover the strangest of legends when left to his own devices, doesn’t he?” she asks, not waiting for a reply and already making her way downstairs to the restricted section. “We only have one book in Mondstadtian about the legend, but it should tell you everything you need to know. Strictly speaking, it’s restricted to loans from within the Knights — but I’m sure we can make an exception for such an upstanding citizen.” She hands him the book, and Diluc notices how slim the tome is as he follows her back upstairs. Aside from being thin, it’s also quite worn, with the binding fraying at the edges and the hard cover material peeling away from the cardboard underneath it. The lettering on the cover was probably once gilded but is now barely visible on top of the dark cover, particularly in the dimly-lit upper floor of the library.
As Lisa fills out the paperwork to register the book as checked out, Diluc wonders idly what other languages the books on this topic are in, and which one Kaeya would have read. He’s fluent in just about every language in Teyvat, save for some of the obscure Natlan dialects, so it wouldn’t surprise Diluc if he’s read every book on the topic just to prove that he can.
Finally, he leaves the library with the book under one arm, promising Lisa he’ll return it within the two week limit, and he hurries out of the Knights’ headquarters, not wishing to encounter anyone else, wanting only to get home and start unpicking this mystery.
///
Il Dottore strides through the gates of Mondstadt with all the self-assuredness of a man who thinks he could defeat everyone here in an instant. The Knights at the gate are welcoming, as they must be — but Kaeya watches from the top of the gates, invisible to the people below, his face set in a frown. If the Doctor is really here to find the lost archon– well, Kaeya’s managed to avoid the Fatui’s notice thus far, but how much longer will it continue? He’s rather fond of his job now, and he doesn’t particularly want anyone finding out about his past — of the three people who know, Diluc tried to chop his head off; Lisa is... well, Lisa is her usual self and therefore quite willing to keep his secret so long as he helps her translate some of her rarer books; and Venti clearly can’t mind all that much if Dvalin hasn’t eaten Kaeya yet. Although, a thought whispers in the back of his mind, he might if he knew the full story.
Shut up, he tells it.
The greetings at the gates have finished, and the group of people moves further into the city, likely heading to the hotel where the Fatui are staying. Kaeya climbs down the city wall and trails them from a distance, mingling and chatting with people as he goes to make it seem as though he is simply out on patrol as usual.
Truthfully, he is eavesdropping on the conversations of the Fatui underlings — which are proving to be much more informative than he would have expected. If they were Knights of Favonius, the conversation would more likely be about who would be shouldering the costs of the next drinking evening. Of course, they have things to say about their bosses, but it’s surprising how they don’t watch their words. Perhaps, Kaeya thinks, it’s because they think so little of Mondstadtians. Well, they’ll learn soon, either by his own hands or by the Darknight Hero’s. Hopefully the latter’s, because it’s less likely to be a diplomatic nightmare.
“You’ve got to wonder, why’d Her Majesty send us? The boss keeps going on about divine power and a sign in the stars... you don’t think he’s going mad, do you?”
“The Third Harbinger was a madman long before either of us signed up. No, my bet is it has to do with whatever the Sixth found when he came over here — remember the meteors? He came back grumbling about the Fool and then vanished off to Inazuma just like always, but my cousin’s in his division and said Scaramouche was muttering about the ‘false sky’ or something...”
“Be a debt collector, they said. It’ll be fun, they said. Never mentioned anything about working under a bunch of clinically insane sociopaths–”
“–Oh, I dunno, I think the Eleventh isn’t so much a sociopath as just a regular old psychopath–”
“–He’s still unhinged.”
It’s not much to go on, although it does confirm that the Harbingers are more feared than liked by their subordinates. Perhaps with a few prods in the right direction, those two might be able to be convinced that working for a quote-unquote ‘clinically insane’ boss is more tolerable with an illicit bonus paycheck as payment for reporting on the Fatui’s activities in Mondstadt.
With that information gathered, Kaeya peels away from the crowds in the main square and heads back towards his actual patrol route, on the opposite side of the city to the Fatui’s residence. He catches movement on one of the rooftops out of the corner of his eye, but continues walking without concern. If there’s a Fatui following him, reacting will only draw their attention more, and if it’s not one of them, then the intentions of his pursuant are probably harmless.
///
Diluc only hears of Il Dottore’s arrival in Mondstadt several hours after the fact, when he arrives at the Angel’s Share to take over from Charles. He spent most of the day absorbed in the book he had borrowed — its narrow spine was quite deceiving, because as soon as he opened it he was assailed by the smallest writing he had ever seen. After acquiring a not-insignificant headache, he at last gave up and decided to spend his evening bartending, where he would be able to fully mull over the few chapters he had managed to get through.
The Knights’ usual table is crowded more than usual, with half a dozen knights crowded around it as they loudly proclaim their distaste for their impromptu visitors. Diluc listens idly as he serves drinks, not expecting them to say anything particularly informative — especially given the lack of a certain blue-haired captain with a penchant for gossip.
But speak of the devil and he shall appear, the moment Diluc notices his absence, Kaeya steps through the doorway. He looks– unusually worried, Diluc thinks. Brow creased, flipping a coin in his hand listlessly. As he approaches the bar, Diluc reaches for a glass instinctively, and by the time Kaeya reaches his usual stool a Death After Noon sits on the counter in front of it. Kaeya raises an eyebrow, and Diluc scowls. He doesn’t need the Captain thinking that he cares. He simply values the free information Kaeya offers when he’s less than sober.
“So, you did take up my recommendation to ask Lisa,” Kaeya starts, and Diluc’s scowl deepens. Evidently Kaeya took a look at the library’s register before leaving work for the day, and the idea that Diluc’s activities are so easily surveilled is unpleasant to say the least.
“You say that like I had any other choice to figure out what the Fatui are up to,” he answers grumpily.
Kaeya hums, sounding amused. “Well, you could always have asked them.”
“Me? The Fatui’s least favourite persona non grata? I doubt it.”
The dim chatter of the tavern patrons fills the silence between them for several minutes, while Kaeya drinks and Diluc fulfils orders from other customers. In the relative peace, Diluc thinks about the book — since Kaeya brought it up earlier, it’s remained on his mind, and in particular the first few lines.
The first, now lost, archon was the god of the cosmos, the archon of time and space. They reigned over the land of Khaenri’ah, though kingdoms as far east as Sal Vindagnyr also worshipped that god. And they walked amongst their people, with hair blue as the night sky and eyes like starlight, blessing them with gifts of visions, protecting them from the violence of the Archon War... But as the wars dragged on and more gods fell, some in Khaenri’ah began to wonder — what kind of power would you gain from defeating an archon?