A/N: This is really just a one shot at the idea of this happening, I am by no means an expert in FFXV lore, but I loved the character of Ardyn and didn't see enough fanfiction of him in crossovers, so I wrote this in like... two days, hope it's good.
Chapter 0: Adagium's Unlikely Summoning
He laid on his back, defeated by the boy chosen by the crystal of light to erase him, he closes his eyes, welcoming a feeling he thought to never have, death...
'Aera... I finally get to be with you...' he smiles lightly before fading away from this world, and onto the afterlife...
However, when he opened his eyes he wasn't anywhere like the Crystal he's been in several times, it was a field of grass it seemed, and some castle walls surrounded him, 'Is this perhaps the afterlife? I wonder where Aera would be? I doubt that Aera from when Behamut tormented me was the real one...' he picks himself off the ground and finds his hat, at least he still had his marvellous clothes and Fedora.
She didn't know what to think, who was this man who - admittedly - dressed like a Noble but seemed to have the air of something else?
This man is middle-aged most likely, with red-violet hair, amber eyes, and strong facial features. He dresses in a black trench coat and pinstripe trousers. He wears a red scarf and a hooded, gray and white flower-print mantle.
The man waves at her and her fellow classmates, "Why hello there, could you perhaps tell me if this is the afterlife?" he asked as if he was talking about the weather, confusing them.
"Uh... no...?" the man frowns for a moment before shrugging, "Oh well, there's always next time." now she was very confused, did the man that she assumed she summoned have a literal death wish, as in wishing to die?
The man walks over to her and pats her on the head, "and who might you be? I have to say I've never seen pink hair before." she glares at him and points her wand at him, his eyes seem to widen for a moment before she yells out "FIREBALL!"
And as such a massive explosion occurred, after the dust settled they look to see the man looking completely fine, but missing his hat.
He waits a moment before patting the top of his head and looking around, after a moment he walks off and picks up his hat that landed a few meters away from him.
"Now I must say, that was an impressive explosion, had I not defended myself I would of been blasted away with my lovely hat here." he does a small bow before putting his hat on and standing straight up, "Now, does anyone happen to know why I'm here?"
Her teacher, Jean Colbert, speaks up, "You were summoned here by Miss Valliere, to be her familiar." the man looks at him then to herself.
"Ah, a Familiar you say? While I've never had a chance to meet one of someone who had one..." the man smiles at her before glancing to the side, as if checking something and clicking his tongue for a moment, "ah, drat, I no longer have a connection with Ifrit, those boys killed him..."
She barely heard him, but heard it anyways, who was Ifrit and why had these 'boys' killed him?
The man sighs, "Oh well, if I'm here I might as well go along with it, you there, girly." he points at her, "Would you like to seal the deal?" she looks at him for a moment, he didn't seem to care about it too be honest.
She walks forward and motions him to bend down, which he abides and wait, she pokes his forehead with a wand before speaking, "My name is Louise Françoise Le Blanc de La Vallière. Pentagon of the five elemental powers; bless this humble being, and make him my familiar." and then she kissed him.
'Well... Wasn't expecting that.' he stands up in full and looks at her quizzingly before he felt a slight burn on his right hand, glancing at it he sees some form of runes being written into the back of his hand, it didn't hurt, but it did give him slight warmth within his hand.
He smiles at her, "Now I'm not one to stand on ceremony, but such an occasion calls for an introduction, please, call me Ardyn." after that the children were dismissed and all but the one who branded him flew off.
'Well, you don't see that everyday.' he turns his head towards his... partner? no that wouldn't be it...
"Excuse me young one, but do you perhaps enjoy walking compared to the others?" he raises a brow at her before she speaks.
"SHUT UP AND MIND YOUR OWN BUSINESS!" he begins walking off, 'Oh? It seems I found a touchy subject, best to apologise.' he walks up by her and walks backwards while ahead as to speak to her, "oh, I didn't mean to offend, I like to think of myself as a traveller, and I do quite enjoy a good walk on nice sunny days, so I was wondering if we were similar in such a way, I am truly sorry if I said something I shouldn't have." he had done exaggerated movements to try and cheer her up with his often aloof personality.
She looks at him for a moment before sighing, "Just shut up already." well, it wasn't much, but she seemed to calm down abit after he apologised.
the two continued in silence before reach a room, which he assumed was the girls room, it seemed to be getting dark, so he excused himself, as it would be improper for a man of his age to be in the same room as a girl her age slept.
After leaving and using his ability to traverse to high locations to go to the top of a tower and he looks up at the moons as they sit in the sky.
"Ah, what a lovely site, although I am curious how a planet with two moons work, I don't need to question it now do I?" she sat on the roof and thought to himself.
'I was supposed to die, so why didn't I? Did the gods see need to taunt me more for my sins? and what of the chosen king? Did he sacrifice his life to end me? if so, my revenge is complete, but now... I have nothing to look towards...' he leans back as to lie down.
'Somnus's Bloodline has ended, while I'm sure Insomnia will be rebuilt in time, it won't be by his blood, So what do I do...? My life at the start was to heal others by taking the star-scourge onto myself, then I became men's sacrificial lamb to rid the daemons once and for all...'
He sighs as he closes his eyes, 'And now? I am summoned to an unfamiliar world to serve a little girl as her familiar... Well, I have no other purpose in my eternal life, I might as well play the cards I've been given.' he sits up and grins at the moons before leaping off the tower and landing on the ground with no harm.
He decides to walk around the castle he found himself at, the technology in this world was seriously out of date, they didn't even have self powered cars! now while he did live 33 years of his life like them, it was over shadowed by the 45 he spent in the modern world of Eos along with the roughly two thousand years he was imprisoned.
He decides to travel to a fountain like area and saw two children, a blond boy and a brown haired girl where flirting with each other by the fountain, so he decided to take another way around as to not disturb them.
He gets back to the girls room, who he remember calls herself Louise, and waits until dawn, as she was already asleep, as she was a student he would wake her up when the sun arose as he wasn't aware of when she needed to be ready for classes.
She felt something nudge her slightly, it woke her up but she still wanted to sleep, "Wake up Master, you wouldn't want to miss classes now would you?" the voice was unfamiliar but at the same time she heard it before, and for some reason she didn't like like.
She opened her eyes and stare at a middle aged man with a condescending smile and odd clothing, "Wah!" she pushes away from him and falls off the other side of the bed with a soft thud.
"Oh deary me, If I had known you were an active waker I would of prepared for such." he walks around the end and stops before the last corner to where she was and leaned around it with a curious expression, "Are you hurt in any capacity?"
After remembering who he was, she got up and spoke, "Well, I'm up, so dress me Familiar." the man stops and stares at her, 'What is with this girl?' he wondered in his head before speaking.
"I apologise, but I must refuse, for it would be inappropriate for a man of my age to strip you of your clothes, even if consensual." even he had limits, he wouldn't undress a little kid naked.
Before she could say anything he turns towards the door, "Now, as a child older then 6, I believe you have enough skill to dress yourself, so I shall await you outside." he steps outside and closes the door behind him and waited.
After about ten minutes Louise comes out and berates him for leaving without being allowed too, but he simply waves it off, annoying her.
They walk to the dining hall and Louise has a meal, due to leaving her to dress herself Ardyn wasn't allowed to eat, which he was fine with as he didn't need to eat like humans do.
He walks off towards where the Familiars are and rest.
After a while the students came out and talked with their familiars, but Louise didn't seem keen on it so he wondered about but before he could walk much the same brown haired girl from last night walked by looking confused and glancing at the students, so he stops for a moment, "excuse me, are you perhaps looking for something? Or rather Someone?" he asked her, making ehr jump slightly at the sudden voice.
"Ah, I'm looking for Lord Guiche." he hums, "he is about this tall." he raises his hand about 5'7'' high, "Blonde." he points at his hair, "and has a rose on his shirt?" and he motions at where the shirt would be on his own body.
"A-Ah, yes, that's him." he man nods, "Then I believe he is over... That way." he points towards the boy with pin point accuracy, making the girl smile and nod to him, "Thank you sir." he smiles and waves, "It is of no hassle for me." she walks off while he waves goodbye before walking off, after abit more walking one of the castle maids bumped into him.
"O-Oh, I'm so sorry sir, I wasn't looking where I was going!" she looked down right terrified of him, and some of the other students and staff were looking to see what would happen.
"It is no problem, I was merely wondering around aimlessly in my own thoughts, so if there is one to blame, it is I." the staff looked surprised while the students seemed to sneer at him, he looks at the tray the girl was holding, "although I am impressed that despite bumping into me you held all those trays up, As I am a gentleman I shall help lessen the burden."
"Ah- I don't think you need to do th-" "Too late!" he had already taken half the trays and smiled at her, "Point at where they belong and I shall get to it." seeing no point in trying anymore, she points at the locations, after about five minutes, rather fast considering he had to balance 17 dishes to start with, he delivered them all to their destination.
After a few moments he hears two loud slaps, he looks over to see the boy, Guiche was it? and the brunette from before with a blonde girl slapping him calling him a liar, 'Oooo, did I reveal something by accident, oh how fun!' he walks over before Guiche points at him, "you, this is your fault that these fine ladies are crying!"
Ardyn raises a brow, "Oh deary me, how could I do such a thing? I haven't even met the blonde one yet!" he cried in very fake sadness while clutching his chest, annoying Guiche, "Do you think this is a joke?" Ardyn looks at him, "No... A joke would be funny, but what I see is a sad excuse of a boy trying to get his way out of a hole he dug himself into. That's hardly a good joke."
Guiche glares at him, "You stupid commoner, how dare you talk to me like that!? I am Guiche De Gramont, Third Son of General Gramont of the Tristan Army!" Ardyn holds his stomach while laughing, "So you are a third choice then?" Guiche glares at him before huffing, "I challenge you to a duel commoner!" Ardyn looks at him in interest before laughing slightly and stopping.
"While it is common for the challenged to choose the place and time, I shall leave such an honour to you." he finishes with a bow as to annoy him some more.
"I shall see you at Vestri Court in an hour!" he walks off while Ardyn smiles, this could be entertaining, he heard a voice behind him speak, "y-you'll be killed..."
He turns to see the maid from before, he smiles and pats her head, "Now now, Many have tried to kill me before, yet I still stand, so don't fret, hmm?" he takes his hat off and puts it on the maid, "how about after it you can return me my lovely Fedora, how about it? as a sort of... Reason for me to survive?" the maid seems to blush slightly before nodding and holding the hat within her hands.
After an hour passes Ardyn and Siesta arrive at Vestri Court, Siesta was scared the nice man who she thinks was a noble without magic may be killed, Louise arrives and starts to yell at Ardyn.
"FAMILIAR!" she walks up to him angrily, "You are going to apologise to Guiche right now!" Ardyn glances around, "Oh my, does the wind carry the voice of someone not needed right now?" after some angry yells she decides to stop trying and watch, Ardyn and Guiche was facing off against each other.
"I'm surprised you came Commoner, have you come to beg for your life?" Ardyn laughs at him, "had I come to beg for some that holds no value, I would of asked you to give me something in return." this confuses everyone, but they continued and let the duel begin.
The boy began with summoning a metal construct of sorts, rather interesting, but he had different plans.
He crouches down and slams his hand into the ground, spikes of earth shoot up and impale the construct into place.
"What the!?"
"He can use magic?"
"How is this possible!?"
He grins before standing up in full, "Let the games... begin." he walks forward while summoning his sword, The Rakshasa Blade, the brother to the blade of the Mystic, Somnus's weapon...
The boy summons six more of the constructs, which Ardyn makes quick work of them, wanting this to be over since he was already bored, he uses warp to appear before the boy with a knife at his throat, "do you yield?"
After a moment a silence, he speaks up, "I... I yield..." Ardyn smiles before walking off towards Siesta, he pats her on the head while taking his hat back, "Told you I'd survive." he begins to walk off before Guiche stops him.
"Wait! who are you?" he turns towards the boy with a smile, he bows slightly towards him, "Ardyn Izunia, a simple man of no consequence."