These are the birthday headcanons for one of oldest fans and Patrons. It has a theme and plot, so it’ll be quite different than usual, having been heavily inspired by Night at the Museum and my Viking AU.
I hope you enjoy this, Tullah 😝
Viking Denmark in the modern world
After being thrown a thousand years into the future, he tries to make sense of the strange new world he’s in, and it’s nothing like Kattegat. More importantly, he goes searching for you, and by some astronomical chance, he finds you. But you’re not the same person he remembers, and you don’t recognize him at all.
Mathias had always told you having you in one life wasn’t enough. That he’d want to find you again in the next, then the one after that until the end of time. But now that the opportunity presents itself, would he even be able to have you?
Content warning: Brief NSFW and violence. R18+ only.
Origins
Mathias can trace his predicament back to his expedition to North America. He carelessly picks up a tribe’s religious relic, not realizing that it will grant his deepest desires. Having you in the next life, wherever — and whenever — that takes him. He goes to sleep, not knowing that upon waking up, he wouldn’t be in the same place, nor the same year. Instead, he opens his eyes and finds himself on a hard bench in Central Park in the company of pigeons. He sits up squinting from the sun, wondering what the hell just happened.
He’s not in America anymore, or at least, not the America he knows. There’s no natives, everyone is wearing strange clothing, and the concrete jungle is a bit nauseating. The buildings are so tall that they’re touching the sky, and there are self-driving carriages carrying people in them! To say he’s overwhelmed by the hustle and bustle of a modern city would be an understatement. But his first priority isn’t to figure out where he is, or when he is for that matter. It’s to look for you.
You’re waiting at a bus stop when he lays eyes on you, and time stops. He enters a realm beyond it, like everything just disappeared but you and him. Nothing matters anymore, not the strange world or era he was in, for you were here. He found you in this place, making this place his. He can barely describe the elation coursing through his body as he runs up to you, eyes wide and heart racing. But when Mathias takes your arms and speaks frantically over you, smile growing, you pull away from him as if he were nothing but a stranger.
“Let go!” You push him, much to his confusion.
“What are you talking about? It’s me!” Mathias talks excitedly, not quite registering the fear marring your expression. He comes for you again, laughing as he pulls you into a tight embrace. With your feet off the ground, you start squirming in his arms, frightened out of your wits. “I’m so glad to see you. I thought I’d never see you again! But really, what is this place?”
“I don’t know who you are, and I don’t know what you’re talking about, so could you leave me alone?” You try to pull away from his unrelenting hold on your shoulders. It’s only when passerby take notice of the situation do you have any hope of freeing yourself. They surround him and give him trouble, shoving him back to give you the chance to flee. “You’re crazy!”
You manage to get onboard while leaving him behind, but Mathias chases after your bus like a furious bride left at the altar. And the way he runs is terrifying. He’s charging after you like a bull, following you street after street for an ungodly amount of time before you eventually lose him. One part of you is relieved that you just escaped a maniac who was likely having a mental health episode, but another part of you is wondering that if by some slim chance that everything he said was justified, who on Earth was this guy?
Taking him under your wing
It takes while before you see him again, but even longer before he convinces you to want anything to do with him. You’ll bump into him in the city where he’s sticking out like a sore thumb, still in the clothes he came in, and when that happens, he’ll chase you desperately for a conversation. Luckily, even he can’t quite master the bustling chaos of New York, let alone outrun a moving car. “Wait, just give me a chance to explain, please. I’m not crazy—” He begs as you get into a cab, to where you just yell, “—just stay away from me!”
After a few more chance encounters, you start to feel sorry for him. He clearly needs your help, and what finally changes your heart is seeing him live in a homeless encampment roasting pigeons so he can eat them. Mathias even offers you one, leading you to believe that he doesn’t mean any harm, but is otherwise very mentally disturbed. “I’m gonna get you some help, okay? Don’t make me regret it.” You tell him, leading the man out of the alleyway and to your car. He jogs after you with a relieved grin going, “I promise you won’t.”
He gets fascinated by everything in your house. The furniture, the kitchen appliances, running water, everything. But that also means you need to teach him how to function in the world as it is. How to use cutlery, the phone, public transport. Good thing is that he’s intelligent and adaptable, so he’ll get the hang of everything in a week. His social mannerisms, however, still need a lot of tweaking. The way he talks to strangers can be passive-aggressive, and he stares a lot. People in New York are like nobody he’s ever seen, and he won’t hesitate to point it out to you all the time.
“What are you doing with your fingers?” He frowns, watching his taxi driver rub his fingertips together.
“I was asking for a tip,” They grin.
“What is a tip?” Mathias asks, his accent and foreign background now more jarring than ever.
“You know, when you think I did a good job and you feel like paying me a little extra for it?” The man says sheepishly, hoping to get lucky with who was clearly a rich tourist. “Just common courtesy around here.”
“But you did not do a good job.” He leans back.
You’re tempted to think he’s a runaway from a mental hospital. And one that’s suffering from delusions that he’s a Viking who time-traveled to present day America as he keeps talking about it. To make things worse, he doesn’t have any form of ID, and you’re hesitant to take him to the cops. You decide to keep him at home while you figure this out, hoping that he’d be gone in a few days. “What can I do to convince you I’m not mad?” Mathias sighs, to where you smile, “You’ll think of something. But it’d probably take a miracle.”
He comes onto you. Mathias has always been an incredibly affectionate husband, and by today’s standards, maybe even too forthcoming to the point of it being problematic. So it’s a given that something will happen eventually. While you’re in the kitchen chopping up vegetables, he’ll wrap around you from behind and press his face to yours — much to your protest. “Stop that, Mat. We’re not like that.” But he just grumbles and stays put, expression hardening as he presses even harder. “Of course we are. You’re my wife.”
He tries to kiss you all the time. With his mouth open and tongue is ready for you, he’s quite the menace when he’s in the mood for some love. You obviously respond by pushing him away, sometimes to the point of shoving him so hard that he stumbles back and plummets onto the bed. Mathias will just sigh and look to the side, a little disheartened, but after a moment of waiting for you to let your guard down, he’ll shoot up like nothing and go back to you to try again. After all, he’s faced your refusal of his advances before.
“Mat, I have a boyfriend. He won’t take kindly to you doing things like this.” You shoot him a heated look.
“Boyfriend?” He laughs breathily over you, pressing his forehead to yours gingerly. “What is a boyfriend?”
Interestingly, Mathias is not that bothered by the fact that you have someone. A boyfriend sounds like nothing compared to what he is. To him, it’s more like playful competition that he can’t take seriously. He’s just that sure of your love for him. It’s only if your ‘boyfriend’ tried anything in front of him that he’d lose his mind, which, fortunately hasn’t happened yet. In the end, he’d probably need you to break the spell and to return home, so if he isn’t able to have you, you’re stuck with him forever anyway. Not that he’s complaining.
You can’t grasp the magnitude of his feelings, nor what it truly means to be his. How could you? You’ve never met the man in your life, but he’s known you for all of his. It’s unsettling how sure he is about you, as well as how comfortable he is around you. He won’t always put in an effort to be decent in the house even when you tell him to, even to the point of being naked. Nudity is no big deal to a Viking, so imagine how he’d feel about being told off by you — his spouse. “What’s the matter, kæreste? Never seen a real man before?”
To remedy this imbalance, he tells you about all the memories he’s made with you. And the way he talks about you is as if he really knows you. Mathias is aware of so many things that would otherwise be impossible without you telling him, such as your habits, likes, dislikes, and the way you think. It’s mesmerizing and magical, just as if he was your lover from a past life. It’s crazy how well he gets on with you, and your chemistry with him is so natural, you start to wonder if you could really love him the way he always says you do.
“I won’t put dill in this. It won’t be the same but you don’t like the taste,” He murmurs as he works in the kitchen. He’s making salmon with a cream sauce, and all you can think about is that he somehow picked up on something you’ve never mentioned.
“How did you know I don’t like dill?” You lift your eyes to him quickly, gaze softening out of pure wonder.
“How could I not?” He smiles gently before returning to the stove. It’s only been a week, and he’s already mastered cooking. “I haven’t been lying to you, eskler. I’ve known you ever since we were children.”
At night, he’ll leave the guest room you told him to stay in and come into your bedroom. There’s nothing you can do as he crawls into bed with you, even wrapping himself around you until all you can feel is him. His arms are coiled around your stomach, and he’s pressing so hard against you that you can feel his bulge from behind. One of his hands goes up to your neck, holding it in a possessive, yet glaringly erotic bid for affection. It’s wrong of you to let him do this, but his touch just feels so right, you let yourself give in to him.
You start having lots of close calls with Mathias. He sometimes stand inches away from your face with your lips so close together, you would’ve ended up kissing him if you didn’t turn away last minute. When you do, he chuckles lowly and says this in a tender voice. “I promise we’ve done a lot more than kissing, eskler. We’re adults, after all.” Otherwise, his stare on you is always too hot for you to stomach, almost as if he has something else on his mind. He makes it obvious that he’s obsessed with you, and he’s losing his patience.
He chases you like crazy. It takes him back to the time before you married him, and that gets his blood pumping like never before. He will corner you against the kitchen counter and won’t let you leave without kissing him. Then, against all your morals, you actually do, which ends up with you two in the bedroom, half-naked and about to make love. Something about him feels so warm and familiar, you don’t act like yourself around him. It’s as if he’s put a spell on you, turning your mind inside out until you can’t think straight.
“I shouldn’t be doing this, Mat. This is wrong on so many levels,” You tear up as you climb off him.
“No it’s not. You know it’s not,” He frowns deeply, taking your hand before you can even get off the bed. He’s that high-strung about you, it’s impossible for you to get any space from him at all. Mathias is just constantly on your back, always pulling you back to him, again and again. “You know I’m the one for you.”
“How could I? Some stranger starts following me around like a puppy and I let them into my home?” You gush, red in the face from shame. Now that you said it out loud, it sounded a lot worse than what you originally thought. “And I was just about to sleep with them? God, I must be out of mind. I have to be!”
“But you’re not! Me being here is proof that you’re not crazy because it was you that brought me here. We belong to each other,” He exclaims passionately, his eyes burning with so much certainty you start caving again. But how could you give in when none of this made any sense, and was cruel to Alfred, who had no idea of everything you were doing behind his back? “You’re mine in all the lives you will ever live.”
Alfred eventually catches wind of what you’re doing. You still haven’t figured out how to explain this to him, and you’ve just been so distracted by Mathias, you’ve been putting reality on the back burner. But that all ends when he swings by unannounced with some food to surprise you. However, he’s in for quite the surprise himself. Mathias is in the living room watching TV while you’re typing on your laptop on the dining table, but that’s when he hears jingling behind the door, so he get up and comes over to your side.
“Hey, babe. They had a pop-up sale on some cookies so I thought I’d drop by,” Alfred speaks mindlessly as he enters your apartment with his spare key, and that is when he lays eyes on Mathias. He is visibly startled as he stops in place, but he keeps his composure. “Oh. I didn’t know you had company. Who’s this?”
When worlds collide
Like any other normal person, Alfred blows up on you when you tell him he’s been staying over the last two weeks. After all, what man in their right mind would be okay with their girlfriend living with another man and not tell them about it? You’d have to come up with some pretty good excuses to justify that, and with the way Mathias is holding you, things aren’t looking good for you. His hands are both sides of your waist like they belong there, and he’s giving the dirtiest look to your boyfriend like he’s the unwelcome one here.
“You need to get him out now.” Alfred demands.
“You don’t understand.” You close your eyes.
“What’s there to understand? That you’ve been living with another guy for the past two weeks and haven’t told me?” He seethes, nostrils flaring. The growing volume of the room alarms Mathias, who stands in front of you protectively. “Not that I’d even let you, but don’t you think you’re crossing the line here?”
“He’s homeless, and he’s not right in the head—”
“So is half of New York, but you don’t see me taking anybody in!” He gestures to the Dane like an alien.
“He’s not from this time period, okay?” You exhale.
“What’s that supposed to mean?” Alfred squints, not at all prepared for what you were about to tell him. “Like he’s from another generation that’s somehow okay with their girlfriends living with other guys?”
“No, I mean he’s a time traveler. He’s a real, bonafide Viking from more than a thousand years ago,” You let it slip, watching his brows go up. “And I know that sounds crazy, but I didn’t believe it at first either.”
“Yeah, you’re right, that is pretty crazy,” Alfred scoffs, shaking his head in utter disbelief, but above all else, a sharp pang of betrayal. “If this is a prank, just know that I really hate it and I’m very disappointed in you.”
“But it’s not, I promise! Why would I pull something that could jeopardize our relationship?” You frown.
“I guess so,” He mumbles, albeit a little reluctantly. “But just run me through your thought process here. How did you come to the conclusion he broke the laws of physics and somehow leapt through time?”
“Well, I took him to the doctor yesterday and he had a bunch of diseases that are impossible to have now.”
“Oh,” He makes a face, shocked and disturbed by how on the nose your explanation was. Now he was really worried you were actually telling the truth. “What else? I mean, you can’t actually believe that—”
“—he speaks Old Norse fluently, doesn’t know what Wi-Fi is, and doesn’t even know to use a toilet.”
“Wow, okay.”
“And I’m sure the Danish are familiar with toilets.”
“Right.”
“And look at him. Doesn’t he look just like Mathias Densen, the Viking earl that lived more than a thousand years ago?” You ask him, pulling up your phone to show him a few images off a website.
“Shit, you’re right.” He digs a hand through his hair.
Your boyfriend is cordial at the start, especially with how bizarre all of this is. He’s also excited to talk to a real Viking, so he springs a bunch of questions on Mathias out of curiosity. The way the Dane answers them only confirms you were in fact, not lying, so he quickly gets onboard with the mission to send him back to the past. You’re all in the kitchen when Alfred drops the bomb on Mathias ever so casually while sipping on a mug. He’s sure you’ve wondered about the same thing, it’s just that he has it in him to actually ask it.
“So, how many people do you think you’ve killed?”
“I don’t know. Maybe hundreds.”
“And does that ever keep you up at night?”
“No, I sleep like a baby.”
“Thought you would.”
Things start to get heated once Mathias reveals that he’s in love with you and has no intentions of giving you up. Alfred was willing to be hospitable at first, but he doesn’t play about you, not even if he’s going up against a warlord turned King. This is his realm, and he won’t hesitate to use that to his advantage to threaten a man who otherwise is impossible to threaten. Not that he thinks he needs to, because he trusts you to stay loyal to him. Little does he know, Mathias has a profound effect on you that not even you can understand.
“You’re never gonna have her. I won’t let you,” Alfred says in a monotone, his expression unreadable as he stares straight at the man. He’s taken on a cold and calculating attitude, a far cry from the excitable nerd he used to be. But Mathias isn’t afraid of him at all.
“Then you will never be free of me.” The Dane smiles contentedly, eyes closed for a relaxed demeanor.
“I’d hate to be that person, but I could always call ICE on you for being undocumented,” Alfred raises his brows at him while he speaks in all seriousness, “I’d do that just so you’d leave my girlfriend alone.”
Shit finally hits the fan when Mathias walks in on you and Alfred in the bedroom. You’re riding him when the door opens, and your head whips to it out of shock. In the next few seconds, everything goes from zero to a hundred as something snaps in Mathias — he’s thrown into a hot and crazed mania, driven insane by the sight of you making love to someone else. The look behind his eyes is as if he’s completely gone, and he storms over with the intention to murder Alfred on the spot. “Mathias, no!” You plead, but it falls on deaf ears.
He pulls him off you and punches him so hard, blood sprays from his nose. But that’s not all. Mathias picks Alfred up by the neck, holding him inches above the ground to choke him to death. If he has to kill him with his bare hands, so be it. And he gets dangerously close to doing it when you smash a vase over his head, getting him to loosen his grip. You help Alfred escape with the skin of his teeth while screaming viciously at him. “Get out. Get the fuck out!” You cry, shoving him back again and again. “And never come back!”
After getting discharged from his hospital stay, Alfred goes looking for Mathias. It’s not the first thing that should be coming to mind after the guy almost offed him, but he has to resolve this once and for all. Because at this rate, someone would really end up killed. And he had a feeling that someone would be him. After a few days of scouring the city, he finds the Dane in an alley in front of a burn barrel and warming his hands. Without even greeting each other, they find that they’re already on the same page about this.
“You don’t belong here.” Alfred tells him point-blank.
“I know,” Mathias murmurs, keeping his gaze fixed on the flickering flames. “But she doesn’t either.”
“Ha! She’s lived here since she was a baby.”
“And she’s lived in Kattegat since she was a baby.”
“Have you not once considered she’s not the (F/N) you know? Yours is probably still in 1000AD wondering where you went,” Alfred shakes his head, frankly exasperated by the other’s stubbornness.
“Then why would I be here if she were not? There has to be a reason for me being here,” Mathias turns to him for a disgruntled look, but above all else was how determined he sounded. “She must be the reason.”
Going back to the past
Alfred goes to the library to do some research on the relic that Mathias picked up. Turns out, it can grant the user what they want most, only with a slight catch. It gives them the means to attaining their deepest desires, not the whole deal. And to reverse the spell, the user has to fulfill their wish completely before having that kind of freedom. So in other words, he has to get you to fall in love with him if he ever wants to return to Kattegat. “Well, it looks like you’re gonna be stuck here as a hobo forever. Not my problem.” Alfred shrugs.
Mathias isn’t disheartened by those terms, even if you did just kick him out for trying to murder your boyfriend. You’ve hated him once, just like you hate him now, so this is just a repeat of the past. As much as that bothers him, he knows he can do this because he’s done it before. Alfred, on the other hand, isn’t convinced he can pull this off at all. While he’s putting back the books he used, he wonders what’s left for the Viking now that they’ll be stranded in modern day America without even two dimes to rub together.
“So, what are you gonna do now that you’re never going back to Kattegat? You have nowhere to stay.”
“But I am going back.” Mathias lifts his gaze to him.
“How?” He shakes his head, eyes narrowed.
“I have my ways.”
“What ways? She thinks you’re an axe-waving megalomaniac, for fuck’s sake. You tried to kill me!”Alfred whispers that last part furiously while pointing an accusing finger at the man, who showed not even the slightest dash of remorse. “And you almost did!”
“And that mean she cannot love me?”
“Yes!” He blurts it like it’s the most obvious point he ever made, but something was still not clicking.
“You underestimate our passion for one another,” Mathias smiles sagely to himself as he recollects the raunchier memories he made with you. And he isn’t afraid to disclose that information to the other man. “When we were together, we made love every night.”
“Okay, I did not need to know that.”
“She was always with child.”
“Didn’t need to know that either!”
It’s understandably very tense between you two at first. Mathias will show up at your door, and still in the last outfit he was wearing when you kicked him out, only for you to shut it in his face. He does this a few more times before resorting to sleeping outside your door, because it’s not like he has anywhere else to go anyway. He’ll do anything for you to forgive him, even if it’s at the expense of your kindness since he’s starving at this point. After days of lying outside your home, you take him in out of fear for his well-being.
When he’s back at your place, he behaves well. He actively helps around the house, doing chores without you asking, and doesn’t even bother you for your affection. You’re barely tolerating him, and you don’t see that changing anytime soon. However, you get a phone call from Alfred that changes everything. Just when you thought you would be keeping Mathias at arm’s length out of respect for what he did to him, your boyfriend is now telling you to throw all of that overboard and do the unthinkable. Giving your heart to him.
“Is Mathias back at yours?”
“Yes, but only because he was starving. Why?”
“Well, we had a little talk and we figured it was best to let everything run its course,” Alfred says. He goes on to explain what he found out about Mathias, the relic, the spell, then how to send him back home.
He also tells you that if everything goes right, you’ll still be here. So if he has to give you up until then, he will, no matter how much it hurts. There’s also some part of you that’s not really you, which explains a lot.
A lot being why you were so uncharacteristically receptive to Mathias in the first place. But as soon as he gets sent home, you’ll return to your normal self again, which is everything Alfred could ever want.
Mathias eases his way back onto your good side. Aside from being a good roommate and giving you space, he will sneak some lingering touches until he works his way up to talking and hugging again. It works better than you like, but Alfred did say you weren’t yourself. You are your past self, or at least partially, but it’s more than enough for a soft spot to form for him. Before you know it, it’s routine for you to sit on his lap and talk to him at night. While nothing happens, it becomes undeniable what’s developing between you two.
“Is it okay for me to put my hand here?” He whispers, letting his palm hover over the side of your face, and you answer him by simply press your cheek into it. You’re looking at him in a way you never had before, with so much love and tenderness that he feels like he’s back home. But then again, you are his home.
You start having dreams about your past. And it’s all so vivid, it feels real. Little do you know, it is, because what you’re experiencing are visions of the life you once lived. Playing with him as a kid, getting chased by him in adulthood, and finally marrying him in the sweet, cypress-scented air. Sailing to new, unknown lands just to give you a better life and a place to raise a family with him. All of it is so familiar, and the memory of Mathias is so beautiful that you end up waking in tears, aching for what feels like a dream of a dream.
Overtime, you remember more about yourself until you’re no longer the person Alfred knows, but the person Mathias does. It’s like your past self is fighting to wake, then on that one fateful night, everything just falls into place. With only one glance at you, he knows you’ve come back to him. You’re staring at him with your eyes wide and lips trembling, almost as if you hadn’t seen him in years. He smiles warmly as he opens his arms for you to run into, and you practically plow into them with tears running down your face.
“Take me home, Mat. I wanna go home.” You whisper into his chest, squeezing him as tight as you can.
“We will, kæreste. You’re gonna take us home now.” He wraps around you assuringly, kissing your head.
The next morning, you and Mathias wake up in the bedroom of your longhouse. He remembers everything that happened, but strangely enough, you have no recollection of being in New York or having a boyfriend there. When he tries asking you about it, you shoot him a weird look and go,“Who’s Alfred?” On the other side of the timeline, Alfred looks for you at your apartment after you text him to come over for dinner. When he does, he notices that Mathias is gone, and upon asking about it, you shake your head. “Who’s Mathias?”
