What Are The Best Undertale Undyne X Papyrus Fanfiction Stories?

I swear, half the time I stumble into a Undyne x Papyrus fic these days it's some flavor of 'they were training buddies and feelings snuck up on them'. That dynamic gets milked a lot—Papyrus trying so earnestly to keep up with Undyne's insane regimen, her gruff exterior slowly cracking at his undying enthusiasm, that sort of thing. It's cute, honestly, even if it's predictable. What I find more interesting are the post-pacifist or post-genocide attempts. Like, fics where Papyrus is grappling with the weight of what happened, and Undyne, who's seen the worst of it, becomes his anchor in a weird way. They're both trying to rebuild a world that feels broken, and they find solace in each other's specific brand of weirdness. It hits different when the usual bombast is tempered by shared trauma. And you can't talk about popular Papyne plots without mentioning the 'Royal Guard Partners' trope. Papyrus finally gets his badge, and they're on patrol together. It's a great setup for banter and accidental hand-holding during monster attacks. It leans hard into the 'competent but still kinda goofy Papyrus' interpretation, which I'm always here for. Honestly, the sheer volume of domestic fluff is what surprised me. Just... them figuring out how to live together. Undyne burning pasta while Papyrus reads her a convoluted puzzle book. It's soft, low-stakes, and sometimes that's exactly what you need after a heavy chapter in the main game.

The relationship between Undyne and Papyrus, or Papyrisk as some fans call it, often builds on a dynamic the game itself only hints at. In 'Undertale', their friendship is already full of boisterous energy, from Papyrus’s enthusiastic admiration of the Captain of the Royal Guard to Undyne’s proud yet affectionate mentorship. Fanfiction writers latch onto that existing spark and ask: what if Papyrus’s relentless, innocent optimism began to chip away at Undyne’s tough exterior in a different way? The development usually isn't a sudden confession; it’s a slow, often hilarious process of Undyne realizing her feelings are shifting from pure mentorship to something more confusing. She might find herself disarmed not by his fighting prowess—which is comically lacking—but by his unfiltered sincerity and unexpected moments of insight. Papyrus, meanwhile, might remain blissfully unaware for ages, interpreting his own increased heartbeats during training as a need for better cardio, which creates this wonderful blend of comedic misunderstanding and genuine warmth. Many stories explore the tension between Undyne’s canon romance with Alphys and this alternate pairing. Some fics exist in an AU where Alphys isn’t in the picture, allowing a clear path. Others tackle the complexity head-on, with Undyne navigating confusing feelings for two very different people, often leading to angst or a gentle, polyamorous resolution. The development frequently hinges on shared activities beyond training, like Papyrus’s cooking attempts becoming a bizarre bonding ritual, or Undyne discovering he’s a surprisingly thoughtful listener during quiet moments in Snowdin. His childlike wonder contrasts with her intensity, and writers show how that balance allows her to be vulnerable in a way she seldom is. The romance matures as Undyne learns to express affection in softer ways—maybe helping him organize his action figure collection instead of just smashing things—and Papyrus responds with his trademark pure-hearted devotion, seeing the best in her even when she feels uncertain. What makes the pairing compelling across so many fics is its foundation in mutual, unwavering belief. Papyrus never doubts Undyne’s strength or goodness, and Undyne never mocks Papyrus’s dreams, even when she teases him. That bedrock of respect makes a romantic shift feel earned. The development often culminates in a scene where Undyne, flustered and avoiding her usual yelling, finally admits her feelings, and Papyrus responds with overwhelming joy and a declaration that this is the best possible outcome, better than even joining the Royal Guard. It’s less about dramatic conflict and more about two wildly different personalities discovering a unique harmony, with his innocence tempering her ferocity and her strength giving his optimism a confident anchor. You finish a good Papyrisk fic feeling like their world is a brighter, warmer place.

I've spent way too much time diving into 'Undertale' fanfics, and King Papyrus is a goldmine for creativity. One standout is 'Royalty Reimagined,' where Papyrus reluctantly inherits the throne after Sans vanishes. The story nails his mix of goofy charm and unexpected wisdom, showing how he struggles with responsibility while keeping his spaghetti-loving spirit. His dynamic with other characters—especially a fiercely protective Undyne as his knight—adds layers of humor and heart. Another gem is 'Crown of Puzzles,' which reimagines Papyrus as a strategic genius who turns the Underground into a giant trap-filled labyrinth. His growth from a naïve skeleton to a cunning ruler is brilliantly paced, with nods to his iconic quirks like his love for capes and dramatic speeches. The fic balances action with emotional depth, especially in his strained-but-loving relationship with Sans. It’s a fresh take that respects his canon personality while expanding it.

I honestly don't think Undyne and Papyrus fics get enough credit for how they can push both characters into genuinely new emotional spaces. A lot of the popular stuff just has them goofing off or being aggressively friendly, which is fun but not really growth. I look for fics where their dynamic forces change—maybe Papyrus's relentless optimism makes Undyne confront her own insecurities about being a good mentor, or Undyne's raw intensity pushes Papyrus to set firmer boundaries or define his own strength beyond just 'being nice'. One I'd recommend is 'Burning Bright, Staying Determined' on AO3. It's a post-pacifist run story where Papyrus decides he wants to understand Undyne's determination on a deeper level, which leads them into these intense, almost philosophical sparring sessions. Undyne has to articulate feelings she usually just screams through, and Papyrus starts to see his own patience as a form of power equal to her physical strength. Their growth isn't about fixing each other, but about expanding their own self-concepts because of the other's perspective. Another angle is fics that explore Papyrus's hidden depths—like, he's not just naive, he's deliberately choosing optimism. I read one where Undyne, after a bad failure, snaps at him about it, and his response isn't to get sad but to calmly explain why his hope is a conscious weapon. That moment forces Undyne to grow past seeing his attitude as childish. Those are the gems: where the ship becomes a lens for examining their core traits under pressure.

Finding adventure fics for that specific pairing can be a real deep dive. You don't see Undyne and Papyrus shipped together too often outside of crack or fluff pieces, so an adventure-focused story is a niche within a niche. I'd hit up Archive of Our Own first and use the right tags. You'll want to filter by the pairing 'Undyne/Papyrus' or 'Papyrus/Undyne', then maybe add additional tags like 'Adventure', 'Quest', or 'Action/Adventure'. Don't be discouraged if the results are slim. Sometimes the best method is to find an author who writes great adventure fics for the fandom and check their bookmarks. I found a solid multi-chapter one last year called 'Royal Guard Training Days' that had them on a monster-hunting expedition in Waterfall. It's less about romance and more about their dynamic, which honestly is the fun part anyway. The author has since orphaned it, but it's still up on AO3.