Summary: You and Erik have to hide your relationship from your brother, Charles...

Warnings: Mild language, some brief making out, sassy Erik and protective bro Charles, be warned...

A/N: Another lovely request from @Umia294 , I hope you enjoy reading it as much as I did writing it! I definitely think Charles is cute but I'd want him as a brother so this kind of made my 'self insert' fantasies come true. Anyways, I hope you guys like this one-shot and as always, requests are open. I may not always get to them but I like to have that option for when I'm hitting a writer's block. Also...that gif....*cough* not me imagining my boyfriend and brother having  a good time together *cough, cough* onto the one-shot!

Ok wait last thing: I was about to upload this and then I thought I had a smudge on the gif so I went to wipe it but it's the satellite dish LMAO I'm SOOO dumb

Words: 4586

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You've never been so thankful for your mutation. All those years of insecurity and self-loathing were a waste of energy. If only you'd known that your ability to shield yourself from anything would protect a secret romance with perhaps the most attractive man to ever grace the planet. You still can't believe he broke for you. His tough exterior, as it turns out, is a front. Just as you can form an invisible defense around your body, Erik Lehnsherr built one around his heart. He froze it over and locked it away. When your brother Charles brought him to the mansion, Erik seemed restless. Like a tiger in a cage. He paced the entire estate, foaming at the mouth with anger and plots of revenge that Charles fought to subdue. Over time, he's managed to dilute Erik's bitterness, but that's not all thanks to Charles...

You helped some.

Charles knows.

But if he only knew the half of it...you muse as you drag a fingertip down the arm secured around your waist.

Despite his good heart, Charles is not always so sensible.

He and Erik are friends. You'd go so far as to say they're close friends.

And you're Charles' little sister...

Water and oil don't mix, you huff.

"What is it?"

Erik's warm breath peels the hair away from your ear. You rest your cheek to his shoulder and tuck an old receipt in between the pages of your book.

"Nothing, just thinking."

"How dangerous."

His sarcasm brings a smile to your face. Erik is always trying to make you smile. He claims you have the prettiest smile he's ever seen and therefore, it is his solemn duty to coax it out of you whenever possible. The problem is, he's so annoyingly skilled at it, that he could have you smiling all day long. If only there were a shield against adoring boyfriends. Maybe then, your cheeks wouldn't hurt half so much and he'd be less airheaded about his accomplishments. Sadly, there is no such shield, and you're forced to bury your smile — and all its supposed glory — in Erik's chest, which puts a matching grin on his face. The ghost of a kiss tickles your scalp as you twist awkwardly in Erik's lap to hide. Laughter rumbles in his chest, just below your chin, and it shakes your head like Jell-O.

"You're incredibly easy to disarm, for a living defense system."

"And you're incredibly annoying for someone so charming."

"Me? Charming?"

Oh he scoffs, but he knows he could melt the clothes off any woman by merely breathing.

You sit back up and hug your copy of Jane Eyre to your chest as Erik hooks both hands under your thighs and hauls you into his lap, this time facing him. Without warning, he leans in for a kiss. You reciprocate immediately, freeing one arm from the book to cup the back of his neck and pull him closer. As if that's even possible. There's no such thing as space with Erik Lehnsherr. He may seem cold and unapproachable in public — and by public you mean with anyone that's not you or Charles — but at his core, Erik is the snuggliest teddy bear of a man. The moment you'd confessed your feelings for each other and shared your first kiss, Erik took it as a ticket towards free cuddling 24/7. Whenever you're behind closed doors, he spins you into his arms and traps you there for as long as he can. You're often in his lap, reading quietly, as he naps, or reads a bit himself. Sometimes you two play chess, but the games are never very good ones, since Erik can't stand sitting across a table from you for more than a couple of minutes.

There's never been a more touch starved man than yours.

He craves kisses and hugs and hand holding.

Run your fingers through his hair and he'll relax until he drops off to sleep.

You really love how touchy he is.

It works out for you, because your love language is physical affection, followed closely by words of affirmation.

Basically, Erik's touchiness and incessant teasing fill your love-cup so high, it's in a constant state of overflow and you've been drowning in him since day one.

But Charles can never know.

He'd kill you –

No, scratch that. He'd kill Erik.

Then he'd ground you forever.

A pair of lips brush the tip of your nose. "Earth to (Y/N)..."

"Sorry," You duck your head, "I um, just thinking some more."

"You've got a crease," Erik remarks. He presses the pad of his thumb between your tightly knitted brows and gently massages the tension away. "Headache?"

"No, I just...really hope my shields stay up so Charles doesn't come snooping."

"Hey..." Erik traces the swoop of your nose as he searches your eyes. "Whatever happens, we'll figure it out. I'm not letting go of you so easily. Not even to Charles. In the meantime," He sighs and sets a hand on top of your leg, absentmindedly beginning to detail it with incoherent shapes. "I trust your shields to hold up. Don't worry about it, darling...thinking too hard will put stress on your concentration and disturb your subconscious."

"Ok," You mumble.

Erik smiles and kisses your cheek.

All of a sudden, his stomach howls. It startles both of you. Erik's hands wring your legs and you grasp a handful of his shirt. As quickly as it came, the growling is gone, and Erik's shoulders shake with silent laughter.

"Would you like to get something to eat?"

"I think you'd like to..." You mutter but of course, you agree.
Plenty of students and professors at the mansion go out to eat, often in large flocks. So far, Charles has yet to question your frequent outings with Erik. Perhaps, without the option to peek inside your heads, he's exercising his natural intuition and simply missing what's in front of his face. That's all well and good for you, since his ignorance allows you and Erik to have proper dates. Occasionally you go as 'friends' with the other mutants, but times like this, when it's just the two of you wanting to grab a bite, you'll exert all the physical affection you want. Erik's fond of resting a hand on your thigh as he drives, or holding your hand nonchalantly while ordering or waiting for a table. When it's Erik's turn to choose the food, he always takes you to fancy places. You, on the other hand, prefer cheaper, quicker stuff. Burgers and fries you can carry to the park. Erik likes courses and wine and the whole chabang. It's a nice contrast to bounce between.

Since neither of you are dressed very nicely, you opt for pizza.

Today, Charles went out of town on business, leaving you and Erik to freely act in love. You went on a walk together, made lunch together, did some sparring, and then separately cleaned up before hiding in your room for some downtime. It's been lovely, not having to be so sneaky. Most days, you and Erik don't get to even kiss each other until the afternoon, when everyone is preoccupied and there's enough time for him to grab you, kiss you, and slip away. Thankfully, no one has ever caught you in the act of PDA. Though, there have been many close calls.

One instance being that time in the library, when Charles almost saw Erik about to slap your butt. You see, Erik is a tease. He likes to pester you, and get you all flustered purely for his own amusement. You discovered just how far he'll go, when you made the mistake of visiting the library with him intending to actually read, not make out in a corner. As you were standing on the balls of your feet to grab a book, Erik snuck up behind you and smacked your butt so hard you almost lost your balance. Lo and behold, Charles happened to come in two seconds after the slap. All he saw was you starting to rock backwards, and Erik catching you.

It's a good thing your boyfriend is a quick thinker.

He reached for the book you wanted and handed it to you whilst cheekily remarking, "Use a stool next time."

Charles wrote it off as a casual, platonic interaction.

All of your close encounters have been like that one; very very close.

Dangerously close.

You honestly can't believe how you and Erik have managed to hide this relationship for months. Between the dates and stolen kisses, someone is bound to notice eventually. Perhaps the most challenging element of dating Erik Lehnsherr, is the nightmare ordeal. Both of you have them. Him more so. As you've gotten to know each other better, he's begun to confide in you in a way he's never done with anyone else. Over tea, and a rainy day's chess game, Erik let slip his 'nightmare' problem. You already knew about Germany and all he suffered there. Losing his family — worst of all, his mother, right before his eyes — and being subjected to testing that he believes has made him into some sort of monster.

What a steaming load of crap.

"You're not a monster, Erik. You're a man who's had a lot of bad things happen to him. Bad things make for a lot of bad thoughts; about others, about yourself, about your past and your future. Your thoughts don't define you, but your actions do. As far as I'm concerned, you might've done a few things you aren't proud of, but you haven't centered your life around them. You're here, Erik. Right here, with me, protecting mutants, fighting for something good the right way. You learned from your past choices and choices people made for you. What I have in my arms right now is not a murderous mutant psycho; I've got a beautiful, sarcastic, passionate, and caring man who I love with all my heart."

That's what you told him, the first night you caught him in the middle of a nightmare.

It's taken a while for him to believe it.

He's come a long way, you note, as the two of you say goodnight at the car. You run in first, so no one will suspect anything. Both of you smell of red sauce and coke. If you enter at different times, it'll be harder to notice. Raven spots you and yells goodnight so loudly, she probably woke the whole hallway. You giggle behind your hands as you make your way to your bedroom. Today was nice...but it was busy, and by the time you're in pajamas and your teeth are brushed, you're ready to crash into bed and sleep well into tomorrow morning.

*Time Gap brought to you by setting up Jumanji for the mutants but having Erik hiding nearby to move the pieces just to scare the kids*

Tomorrow comes.

And so does your brother.

Charles asks you to get coffee with him that morning, so the two of you drive into town and enjoy a cup on a park bench. This whole mutant initiative has kept Charles quite busy, so he makes an effort to spend time with you whenever possible.

Regular coffee dates have become the go-to.

"So," Charles sips his drink. "Anything interesting happen while I was away?"

You're rather good at hiding your relationship with Erik when it comes to literally shielding yours and his thoughts from Charles, but guarding your mouth is not your forte. "Uhhhh well I mean, you were gone for one day, Char."

Great.

Now he's suspicious.

"A lot can be done in one day," He remarks.

The best way to save this is to feed him half of the truth. You swallow a mouthful of hot coffee to calm your nerves.

"Well, I went for a walk, ate lunch, sparred with Erik and then I read a bit but I got a hankering for pizza so I went and got some for dinner and then I came back but pretty much everyone was out of sight. I saw Raven though."

All of it actually happened, only...you did most of those things with Erik. You continue to sip at your coffee, acting as casual as possible to counter the half-truth. Can he hear you lying through your teeth? Mind reading, you mask a scoff with an exaggerated swallow. Lucky bastard. Having access to Charles' thoughts would make this secret relationship with Erik even easier. You'd be able to shield your own thoughts and stay up to date on Charles' suspicions. The closest you've got to telepathy is the universal human ability of discerning facial expressions and any physical display of emotion. A peep at your brother's face, and you'll know whether he suspects something. That one peep is a risk you aren't willing to take, so you aim your eyes straight ahead. A little boy sprints through a flock of pigeons. You laugh.

Charles joins in.

That's a good sign.

If he saw your lie, he wouldn't let pigeons distract him.

"How was your trip?"

"Productive. I believe more people in positions of power are coming to understand the mutant cause...a few have reached out to me already. I have high hopes for us."

You lodge your coffee between your legs and reach for Charles' arm. His eyes flicker towards your face as you gently squeeze his bicep.

"I'm proud of you, Charles...you work so hard to keep us safe."

Charles looks as though he could cry.

He smiles instead, raising his arm to draw you close. You whisper a sigh and get cozy in his embrace. The coffee cup heats your inner thighs as you rest your cheek against Charles' scratchy tweed blazer. Charles smoothes the creases in your jacket through deep strokes of his thumb, absentmindedly rubbing his palm along your arm as the two of you watch the park's daytime buzz bloom. Business associates gather for a morning walk; couples appear in vibrant athletic gear, squeezing in cardio before the work day begins; and individuals lead their dogs on leashes or push children in strollers. As you watch people go about their morning, an age old ache stirs. How many of these are mutants, you can't help but wonder. What about the boy trying a skateboard across the way? Will he wake up one day, setting his sheets on fire? Or the woman, reading a paper by the streetlight, her dog peeing at its base; has she isolated herself from humanity, afraid of the power at her fingertips? How many others have to suffer, hide from the light, because everyone lives in fear.

Both you and Charles struggled with your mutations as children.

The fact that you had each other to confide in, was nothing short of a miracle. Many — if not most — mutants are alone until someone collects them. Unfortunately, these 'collectors' aren't known to be 'good people.' They aren't like Charles. They prey off the lonely, recruiting them out of self-interest.

Charles collects mutants for their best interest.

He wants to be a home for those in need.

The X Mansion is a family of outcasts.

Not a Hitler Youth program.

Despite Charles' good intentions, you find yourself beginning to doubt. Not Charles, no, his heart is clear. He wears it on his sleeve; it would be impossible to witness all the good he does and come to any conclusion other than that he is a kind man with a passion for protecting the weak. However, Charles' efforts, while valiant, and so far successful, cannot prevent tragedy from striking. Gathering all the mutants in the world will do nothing if the world decides it is sick of outreach programs and reform bills and would rather mutants go back to hiding. An angry, pitch-fork armed mob is always lurking, scouting for an opportunity to assault change. While you applaud your brother's determination to house, teach, and protect mutants, especially the youth, you fear that normals and evil mutants alike, will rise against the X Mansion, and crush Charles' hard work.

What then?

Fight, you pout your lip and feel the hard scuff of the tweed. There's nothing to do but fight back. Defend ourselves.

That is where you and Charles cannot agree.

Erik agrees with you.

In fact, he'd rather start the fight.

You just want to stay safe, and feel free to throw a punch if you've been punched. You don't want to be a doormat for the world to stampede.

But Charles turns his nose up at the thought of violence, even in self defense, he sees it as a snowball effect.

That is why you have to keep your boyfriend a secret. Because if Charles finds out that you remotely agree with Erik's 'violent doctrine' and that you're dating him, he's sure to lose his mind. What brother wouldn't? You're his younger sister. He's been your best friend since as long as you can remember. All his life, he's watched out for you, defended you, taught you to harness your gift. He paid for your education and he housed you when you were old enough to go off on your own. Charles has always been there for you, and for him to let you go, to hand you over to a man he doesn't see eye to eye with, his best friend?

Out of the question.

So you keep the secret.

"I love you, sis. I'll keep you safe. You come first, always."

He kisses the top of your head.

You feel too sick to finish your coffee.

*Time Gap brought to you by Erik throwing knives with his mind to vent*

"We can't, (Y/N)."

"I know but...you can't expect me to live my entire life lying and hiding! Isn't that what united all three of us in the first place? Wanting to escape from that life? And what — now I'm supposed to slink around my own house, avoiding my own brother?"

Erik jumps to his feet and crosses the room in two strides, hastily shutting the door. You fold your arms across your chest and collapse into the nearest tufted chair. He can't look at you; that's how upset he is. The man can bend metal from miles away with his mind and he couldn't shut a door from across the classroom? You want to smack your head on the desk. Better yet, smack Erik's head. For months the two of you have been sneaking around together and neither of you have suggested coming out with the secret. Yesterday, you wouldn't have given it a thought. Sure, you've felt bad for lying to Charles, but it's never affected you like this before. Your chest screams a dull pain, like your heart's been beaten black and blue. You haven't eaten all day. Ever since getting coffee with Charles, you've felt too nauseous to think about food. This secret is like a parasite, devouring you from the inside out. If you could hold a secret in your pocket, it would combust and burn a hole straight through.

Not knowing what else to do, you ran to Erik.

Who else could you talk to?

It's your secret after all.

In seeking comfort, you get a pig-headed boyfriend.

"We've talked about this." Erik turns away from the door, unable to meet my eye. He stalks towards the desk and plays with a dish of paper clips as he speaks in an exasperated tone. "If Charles knows, he'll be angry. He doesn't agree with my views, we fight over it enough as it is. The last thing any of us need is a romance thrown into the mix. Charles will despise you for going behind his back and he'll despise me for 'corrupting' you."

"Yes but he's going to find out one way or another and if we tell him now—"

"We'll still hurt him."

"But not as much as if we wait!" You cry, leaping at once from your chair. "Erik, baby listen to me: Charles is mainly going to hate us because we're lying to him. The longer we wait, the worse the damage, because we're prolonging the lie! Don't you see?"

You stare at him expectantly, half a breath away from his shoulder, which he's propped between the two of you like a shield. Hardly much protection, and you would know. Refusing to look at you won't hide his feelings. Quite the opposite, actually. By avoiding your desperate gaze, Erik proves that he's wrestling with himself. You let a sigh roll off your shoulders as you study the clench of Erik's jaw. He's turned his cheek just right, totally veiling his expression as he dances paper clips around the desktop. Your eyes drop from his side profile to the quivering metal stationery. The paper clips are unraveling. They jerk, crack, coil and slowly decay into tangled webs of nothing; crushed so tightly, that there's no space left to manipulate. Erik drops them suddenly, a ring of metal carnage.

"I don't want him to hate me..."

Erik's voice is so small.

So fragile, you hardly recognize it.

He clears his throat as if to correct his vulnerability. "He might be your brother, but he's my friend...the only one I've ever had..."

You slide up against him, hugging his arm and kissing his shoulder.

"I want you," Erik breathes. "I want you...but I don't want to lose Charles either."

"So you want to keep the secret...to keep both of us?"

Erik leans his forehead to yours and nods weakly. "God," He grumbles. "What is it with you Xaviers..."

You chuckle. "I tried to warn you."

"You did."

"And you didn't listen," You huff. "Per usual."

Erik smirks, "I never did like listening to good advice."

"Oh yeah?" You murmur as Erik's attention shifts to your tightly sealed lips. A hum rumbles in the depths of his chest as his hands travel down your spine to grasp your hips, pinning you to his front.

It's therefore unsurprising when he presses his mouth to yours in a fevered kiss, craving affection after dissecting such a tender topic. You wish you could say you restrained yourself, but that would be a raw lie. As soon as Erik's lips met yours, you completely stitched your bodies together, easily giving in to the outpouring of emotion. His hands were kneading through your shirt and yours were trailing at a torturous pace up his dress shirt and into his hair. Ignoring how perfectly he'd styled it, you disturb the gel, and rake your fingernails over his scalp, delighting in how goosebumps are left in their wake. Erik groans. Forcing his weight onto you. Your knees buckle, and he sweeps you up, clearing the desk with his mind. The paperclip graveyard and dish go toppling over the edge as Erik sets himself between your legs and inhales your kisses.

"Oh my —"

You shriek.

Erik just whirls around, raising a letter opener from Lord knows where and pointing it at Charles' throat.

Wait—

"Charles!"

"(Y/N)!"

"What the Hell are you doing in here!"

"I was looking for someth — Erik would you please put that thing down!"

Erik rolls his eyes and tosses the letter opener away.

Charles trips backwards against the wall, tearing his hands through his hair and down his face. You glance at Erik, who, despite the rigid line of his shoulders, seems virtually at ease. He shrugs, like you've not just been caught making out in an empty classroom by your brother.

"Will someone tell me what the Hell I just saw?"

"Uh–" Your eyes dart between your panicked brother and your quiet boyfriend, who stare each other down.

Charles' face is a hundred shades of red; it's impossible to guess which are embarrassment, shock, or anger.

"Char," You begin tentatively, holding out both hands as you slide off the desk. "It's not what you think—"

That's when Erik finally decides to open his trap.

"Actually, it is."

What!?

"So you're messing with my sister, behind my back, in my own damn house?" Charles growls.

Erik's confidence does not waver. He rolls his shoulders back and takes the accusation like a grain of salt. "Dating. I'm dating your sister, behind your back, in your own damn house."

"That's not what it looked like," Charles snaps.

A rueful smile graces Erik's lips. Your internal uh-oh alarm chimes as Erik lets out a scoffing laugh, "Boyfriends kiss their girlfriends, Charles, didn't you know?"

Charles launches himself at Erik.

"STOP!"

Charles bounces off an invisible wall. He would've fallen on his ass if you hadn't caught him with another shield. Your brother scurries to stand. He brushes himself down without so much as a thank you for breaking his fall.

"Move this, (Y/N)," He orders.

"No! Not until you listen to what we have to say!"

"I don't give a damn what he has to say!" Charles yells. "He–" He jabs a finger at Erik on the other end of the forcefield. "Went behind my back to snog my sister and waited how long to tell me? Months I'd guess...by how cozy the two of you seemed. I thought you were just friends! I thought we were friends, Erik...clearly I was wrong. You've been a traitor all this time..." He descends into a fit of bitter laughter. "And to think that I trusted you."

The look on Erik's face just about breaks your heart in two.

"Charles–"

"Don't. You. Start." Charles rounds on you, steam stems from his flaring nostrils. He's already worked up a sweat, bellowing in Erik's face. "You should know better! I look after you — I train you and you throw it all away because of him? Just because he's my friend doesn't mean I trust him to care about you, or protect you like I do. He wants revenge, (Y/N). He wants violence and if he had his way, he'd bring chaos into the Mansion; he'd hurt us, he'd—"

Charles' voice cracks.

"He'd hurt you..."

"Maybe," You whisper. "But why shouldn't I love him anyway? I love you too, Charles, and you're hurting me right now."

The room goes quiet.

Nobody speaks for a solid five minutes.

You can hardly breathe yourself. All of your focus is on protecting Erik from Charles' rage. With all the attention you're spending on the forcefields, you've completely abandoned both yours and Erik's minds, leaving them open to the mind reader in the room, who almost immediately dives into your memories, scanning hundreds of dates and stolen kisses, probing for some sign of wrongdoing on Erik's account. Search as he may, Charles cannot and will not find anything incriminating.

Erik has been a gentleman.

He respects you.

Despite what Charles might think...Erik really loves you.

You see the shift in Charles' body language as he comes to terms with this sudden flame between his sister and best friend. His shoulders sag, and his face falls, but he breathes through it.

In time, he meets your eye, and smiles tearfully.

"Okay..."

You wipe away the tear that's crept out of the corner of your eye, and relinquish the force fields.

Erik looks up at Charles, holding his breath...

"You love her."

"I do."

"So do I."

"I know."

Charles sighs, turning to leave the room. Yours and Erik's eyes follow him to the door, where his hand hovers over the doorknob. He halts. One second...two...and he grasps the knob, turns it, and then catches Erik's eye over his shoulder.

"Treat her well, my friend..."

The ominous, 'or else' goes without saying.