Ever since you mentioned Ace and Nox meeting I literally cannot stop thinking about it because Ace would just. Be so confused about Nox existing. (Also I'm just seeing Tredd or Luche introducing Nox to Ace's cooking)
OHHHH OH YES THAT. I’ve been meaning to do something with that *rolls up sleeves* HERE WE GO THEN:
IN CANON, Noctis has something of a …. Talent for either stumbling into other dimensions of meeting them (the hiso hiso and the miqo’te lady side quests, as well as Dissidia NT if you wanna count that which I DO) and Ace has something of a penchant for running to trouble because honestly the Astrals need entertainment from somewhere and apparently they don’t get cable or streaming in that blue Void of theirs. So the way I see it- either Nox accidentally goes to Ace’s universe for a few days, or Ace accidentally goes to Nox’s for a few days.
Because I love both ideas, I shall do both. This is gonna get Very Long™ (edit: It’s almost 3k words WHAT IN THE WORLD ME-).
Option One: In Which Nox Really Needs To Watch His Step More and Axis and Fem!Nyx Get Dragged Into Things.
-It starts when Nox trips. Seriously. That’s how it starts. Nox trips and Something Happens in the split second his best friend and his girlfriend/wife grab his arms to steady him and then- they’re falling. Like- seriously falling. Falling from 10+ stories up kinda falling and Axis is cursing the entire time Nyx grabs Axis and warps to the relative safety of one rooftop, expecting Nox to do the same. He does, but he misjudges the threshold of Impact Resistance that the roof he lands on holds (that or the Astrals are laughing at him again). It breaks under him and he topples down in a crash of magic and debris onto a slightly cushy landing of broken crates (hey better than concrete or solid ice) and … glass?
-Why are his clothes soaked with what looks but does not smell or feel like blood?
-He is just pondering this quandary (is this whiskey? It smells like whiskey did he just crash through the roof of a bar?) when the door to the storeroom in which he’s landed slams open and in rushes a very unhappy looking Galahdian with a very large knife and braids in a style he doesn’t recognize. The Galahdian stares at him with wide, vaguely disbelieving eyes, Nox barely refrains from summoning a knife of his own (he’s not a threat, he’s a Galahdian twice-over now and Axis insists that means no Galahdian in their right mind will try to hurt him without due provocation).
-(He really hopes accidentally falling through the ceiling and ruining who knows how much whiskey/wine/whatever doesn’t count as due provocation.)
-Thankfully, all the stranger does is slowly sheath his knife and look both exasperated and amused, “Care to explain what just happened?” He says and something inside Nox … jolts.
-Nox swears he hears the low whispers of thunder and magic in the man’s voice, buried as it is under a veil of humanity and normalcy. But surely that’s his imagination.
-Nox pries himself free of the rubble and ruined alcohol, inwardly mourning his no-doubt ruined clothes (they’d been so comfy too) and the stranger looks sympathetic as Nox futilely tries to wring a bit of the alcohol out of his sleeves as he answers, “I have … honestly no idea.” Because weird as his life is, even he usually doesn’t take a step forward, trip and somehow go from inside the Citadel to somewhere in the … he’s going to assume he’s in the Galahdian district because this is a bar with a Galahdian worker (owner?). The last time he blinked and went from one place to somewhere drastically different had been-.
-Dissidia. The Hiso Hiso.
-Astrals please no.
-Nox looks up and can hear the slight beg in his voice as he says, “Please tell me I’m still in Insomnia during the reign of King Regis Lucis Caelum.”
-The stranger’s eyebrows go up almost to his hairline (which is a fair reaction to his question) but answers, “….Yes?”
-Oh good. Now to figure out if he was in his Insomnia or some kind of parallel dimension because at this point he’s not very optimistic on his odds.
-He opens his mouth to make his excuses and get out of there when the stranger cuts him off with a bemused, “Need a new shirt? You can borrow one of mine.”
-He blinks, narrows his eyes in instinctive suspicion, “Why would you help me?”
-“You’re a kid,” points out the amused man, “and a Galahdian.”
-Nox refrains from pointing out that he’s nineteen and technically married, because a new shirt sounds nice and this is the one day he didn’t pack a spare outfit in his armiger. The man takes him to a different room of the definitely-a-bar and produces a spare shirt (short-sleeved unfortunately but Nox will take what he can get) from somewhere, which Nox takes gratefully. His pants are still a mess, but at least he doesn’t smell so strongly of whiskey. He’s thanks the man (who introduces himself simply as Ace) profusely and offers to try to pay for the damages (not like he can’t afford it with a prince’s allowance). Ace turns him down with a shake of his head, reaches out to lightly touch Nox’s elbow (the man hasn’t commented on the scars the t-shirt reveals, Nox is grateful for that too).
-The moment they make contact, the world turns blue and violet. Nox can feel the other man’s magic, pulsing under his skin like the tooth-shaking rumble of thunder and the flicker of lightning in the far distance, taste the ozone on his tongue and feel the jungle rains Nyx speaks of so fondly. Ace’s magic feels like the jungle and the wilds and yet also like the soft snows that settle over a battlefield after the bodies have cooled and Nox’s gaze snaps around in astonishment. He can’t stop himself from reaching out with his own magic in greeting-curiosity-shock toward this- this other Lucis Caelum (sibling? Is he in his home dimension or another’s? Is this man his brother or someone who was never born in Nox’s world?).
-(To Ace, the teen he’s just touched suddenly seems to burn like a star barely captured in flesh, his eyes glow red and Ace can taste blood on his tongue, feel it drip down his chest from the gaping sword wound he knows isn’t there. He can feel the teen’s magic, like crushing ocean depths and the broken, too-deep hush of old ruins. He can feel ash caking his skin like being back in the rubble of his home village. In the back of his mind he recoils, because soul is magic and magic is soul and this teenager’s is a blood-stained, centuries old battlefield).
-They both stare at each other for what feels like too long and not enough before Ace jerks his hand away like he’s been burned (maybe he has, Nox’s magic is still too much for his skin sometimes, still lashes out when he’s too startled to stop it). Ace cradles his hand and curls his magic so tight into his soul Nox can barely feel it (wouldn’t feel it if he didn’t already know it was there). “Well,” Ace manages after several more seconds of mutual staring, “I wasn’t … expecting that.”
-Nox blinks twice, feels realization settle in his bones, “You don’t want anyone else to know.” He can feel it in the way Ace is hiding himself, see it in the wary glint of silver eyes. He understands perfectly. He hid from Regis too for as long as he could.
-Ace laughs a little breathlessly, “You don’t?”
-Nox isn’t given a chance to answer, because that’s right when Nyx and Axis finally figure out where he is and how to get there without jumping through the hole he left in the bar roof.
-He can hear Axis flinging open the door to the bar and Nox is instantly grateful that it’s empty of everyone but him and Ace because his Shield almost bellows through the empty building, “Nox. Izunia. Lucis. Caelum. Arra. Ulric.” Nox hunches his shoulders, hears Ace sputter beside him in confusion at the ridiculous number of last names Axis used.
-“In here, Axis.”
-Axis and Nyx poke their heads in the back and Ace’s sputtering gets louder, then quiets as Axis storms over and slaps Nox across the back of his head and snarls, “What did you just do?”
-“Fell through the roof of a bar and made a new friend,” Nox snarks back past the sting in the back of his head, “Axis, Nyx, this is Ace, Ace, this is my friend and my wife, Axis Arra and Nyx Ulric.”
-Ace definitely makes a strangled, confused noise, silver eyes wide before he takes a deep breath, exhales slowly, and announces, “I’m getting everyone a drink. Go sit at the bar.”
-Ten minutes later, the bar’s sign reads “closed”, Ace has gotten everyone drinks and served up some kind of Galahdian dish too spicy to be healthy (but one Nox loves anyway, this guy is a great cook), and they’ve all concluded that Nox straight up tripped into a parallel dimension and dragged Axis and Nyx along with him. Because Ace is certain that he knows Axis Arra and Nyx Ulric and they should know him (he also gives Nyx several looks that are a mix of horrified, confused, and extremely amused, which Nox doesn’t get at all).
-Apparently, Ace is the result of Regis and a Galahdian woman having a night, no, he has not told anyone else, and yes, he really would like that to stay a secret. Nox has no qualms with that, Axis just smacks Nox over the head again because parallel dimension and Nyx stares maybe too intently at Ace’s braids.
-Because apparently braid meanings and symbols are a bit different in this dimension. Or something. And it’s confusing Nyx to no end.
-“So,” Axis sighs finally once his temper has been settled, “what do we do now?”
-Nox shrugs, “Don’t get killed, don’t make trouble, and wait for either one of our Astrals to come fix it or for it to wear off on its own. These things never usually last long.”
-Axis, Nyx, and Ace all stare at him before Nyx sighs into her hands, “Nox. Babe. Love of my life. Tell me you did not just imply that this is a normal thing for you.”
-“Well- I wouldn’t say normal but….” Axis turns to look Ace straight in the eye, without a word, Ace passes over something much stronger than before. Nox feels vaguely insulted. He’s not that bad is he?
-It takes three days and one very annoyed Shiva (apparently the Astrals of this universe barring Ramuh are jerks?) for the “Trip” to wear off, during which Nox, Axis, and Nyx all lie low at Ace’s place. And by “laying low” what Nox really means is stay well away from the Citadel and any potential Dad Confusion and get gawked at by the various glaives that visit Ace’s bar. There’s no hiding that Axis is from another dimension, though Nox takes care not to go by Lucis Caelum or Izunia around them, just Ulric (which, of course, gets him stared at even more than being an LC, though not as much as his Nyx gets stared at, because Nyx is a guy here and apparently seeing a female Nyx is breaking everyone’s brain. The Libertus of this world just about has a heart attack when he comes in and sees two Nyx’s of opposite sexes staring each other down with trouble-making grins).
-(Nox was the only one who didn’t choke on his drink when his Nyx cheerfully announced to all and sundry that her counterpart was hot and clearly anyone would be lucky to land a date with him. Axis dryly pointed out that it still counted as narcissism if you complemented your counterpart, Nyx just laughed and flopped onto Nox’s legs like she was queen and he was her throne, which made the male Nyx stare and Ace crack up laughing).
-Eventually though, the Trip wears off and they find themselves back in the Citadel with an adventure to tell and a bunch of Very Panicked Adults who want to know how they disappeared for a week and why (and a list of names to check because Nyx might never have met an Ace in her childhood, but that didn’t mean one might not exist and Nox is nothing but thorough about his family).
Option Two: In Which Ace Has A Very Strange Week
-Ace has gotten used to the fact that life (the Astrals) like to mess with him. It’s just- it’s a thing. It’s a thing he hates but there it is.
-But he’s still not used to the entire world glitching out around him like a video game, tripping on air and then landing not in his apartment where he was standing five seconds ago but on the marble floors of-
-The Citadel.
-Great.
-Ace scrambles to his feet, hoping against hope he can sneak out before whatever trouble is coming next can find him, only to hear someone order him to hold still and explain his arrival, look up and see-
-Nyx?
-No wait. This was a woman. A woman who could have been Nyx’s twin, but a woman.
-W h a t ?
-The woman appears to be of similar opinion, eyeing him in confusion before glancing at the other person in the room, “Friend of yours, Nox?”
-Magic swells over him as Ace turns to look at the “Nox” person and he has maybe five seconds to register the inhumanly old gaze and the angry claws of magic sinking into his skin before his own magic reacts against his will, shoves outward in a flicker of violet and ghostly royal arms. It’s not, creepily enough, enough to shake off the foreign magic, but it is enough to startle the Lucis Caelum he doesn’t recognize into backing down. Red eyes turn blue and blink at him while Ace struggles not to swear a blue streak at revealing himself in the Citadel, then the strange Lucis Caelum says, “Oh. You’re not from around here. Let me guess, the world glitched out, or you tripped on thin air, or something happened and now you’re not where you were a few seconds ago?”
-Ace decides he both does and doesn’t want to know how this guy knows that and stiffly nods. The teen (Nox? He was pretty sure this guy’s name was Nox) nodded back, looking far to calm for the situation, and turns to the Nyx look-alike, “Come on then. He can slum at your place until we sort this out.”
-The woman raises her eyebrows in a miffed expression that Ace … knows (oh no. Oh no-no-no this better not be what he thinks this is, his life is not a sci-fi show and this better not be that one episode those kinds of stupid dramas always throw in-), “I’m sorry, when did we agree on that?”
-“The alternative is to stand here and get caught and then explain to my father that no, he doesn’t actually have yet another illegitimate son running around. What’s your preference?”
-They go to the woman’s apartment.
-It’s Nyx’s apartment.
-Same address and nicknacks and everything. Just … missing all traces of Selena or Ace himself. There’s only a few traces of Lib and some scattered objects that clearly represent someone, but Ace doesn’t know who (he has a nasty suspicion its the teen in charge of this escape, the one with long black hair and strong magic and several braids that look a lot like Arra and Ulric braids but … off somehow).
-In the safety of the apartment that is Nyx’s but not, Nox introduces himself, then introduces the woman as … Nyx Ulric.
-Ace maybe gets weird looks from them when he gives into the urge to swear. Because really? REALLY? This is his life now.
-Nox gives him a sympathetic look and a pat on the shoulder and promises to have Shiva sort things out (then shrugs off the stares Nyx and Ace give him at the casual implication that he can boss around an Astral or three). Nyx shrugs and says Ace is free to take the couch, but only if he tells her stories about his world, once Nox and Ace convince her that yes Ace is from another world.
-Naturally, because fate hates Ace, the Libertus of this world walks in on them in the middle of their plotting. Libertus is even more skeptical about a “Lucis Caelum from another world” but Ace has pictures of him and Nyx and Lib and those plus his braids (which are similar but also not to the Galahdian braids they are used to) is enough to sway him.
-It takes a week for Nox and apparently the rest of this dimension’s Astrals to sort everything out (Nox comes back to the apartment at one point snarling about wanting to kick dragon tail and roast fish innards, Ace can relate), during which Libertus and Fem!Nyx alternate between tiptoeing around him and pestering for information (Nyx goes … very, very quiet when Ace asks about her Selena. Ace doesn’t ask again, and is grateful when Nyx lets herself be distracted with pictures of her counterpart)
-(“I’m hot,” she announces smugly, “Lib you owe me twenty gil.” To which Lib sputters, because apparently that bet had been made five years ago when drunk and could not be expected to be valid because really what are the chances of running into an alternate dimension Lucis Caelum that knows a male Nyx? Fem!Nyx gets her money anyway with a mischievous grin that makes Ace ache a little inside).
-Nox, who is far more entertaining to be around than Ace expected another Lucis Caelum to be, finally gets things sorted out and arranged for his return. Ace shows up at his proper apartment a week after tripping into another world and is instantly mobbed by a frantic Lib, Nyx, and Selena who do not believe him about parallel worlds until Ace whips out the photos and phone recordings he got.
-(“Huh,” Nyx breaches the silence after they’ve all seen the video other!Libertus took for him of Fem!Nyx and Nox kicking each other around a training ground, “I’m hot.” Ace laughs, Lib just groans and slaps Nyx on the back of the head because that’s not the issue here, Nyx.)