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Heartwarming / Undertale

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"...Be good, won't you?"
"seeing the hope and happiness that undertale has brought to people...
it fills me with determination."

Undertale is very well known for touching people's hearts, and these moments definitely prove so.


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  • Toby's tweets about Undertale frequently have comments like "People tell me that Undertale helped them through a hard time, or made them want to be a better person." It's an amazing show of just how this game has touched people who have played it.
  • It's very clear that one of Toby's primary goals with Undertale was to give commentary on and open up questions about human morality, with it being such a massive Deconstructor Fleet on tropes like Video Game Cruelty Potential and the way Save Scumming can be used like an Omniscient Morality License. Now, bear that in mind, and look at the way the video game community has treated Undertale: go to practically any message board, comment section, blog post, etc., and you will find many, many, many people saying things like "After only an hour of playtime, I knew I could never do the Genocide route", "I felt bad for telling Sans his brother isn't cool - how could anyone even think of doing the Genocide run?", and "I can't even bring myself to kill one Froggit." You'll also find people who started a Genocide run but soon found themselves regretting their choices so deeply they Reset to fix their mistakes, with the citing breaking point often being having to fight an especially lovable character like Toriel or Papyrus, as well as people who talk about completing the Genocide run with sincere, genuine regret, like it's the biggest mistake they ever made as a gamer. Sure, there's plenty of people out there who claim to have played the Genocide run without batting an eye, but for every person doing so, there's at least a dozen others saying the opposite. Considering this is the gaming community we're talking about, with all the ugly stereotypes and negative reputations it's spawned over the years, a response like this goes beyond just being refreshing - if you take Undertale seriously, as more than "just a video game", as the moral commentary it was meant to be, then being part of the fan community can do incredibly healthy things to your faith in humanity.
    • In particular, statistics show that a majority people very likely stopped a Genocide Route at a very specific point. What was it? Papyrus. That's right, his nonstop kindness and understanding even if you kill him got a large percentage of people playing Genocide to pull a My God, What Have I Done? and stop then and there. People say that even if they were slightly bothered about killing monsters before, at least they attacked you first, so you could slightly justify it as self-defence. They just couldn't go through with killing a guy that just wanted to be your friend, or they felt massive guilt after doing so.
  • The game has a massive fandom, and with a large fandom comes lots of Fanfics. What is, by far the most numerous (with several of them being by far the most popular) fanfics? Ones where Asriel is saved. People really want to give him the happy ending he can't get in the game.
  • Scrolling to the Kickstarter page for Undertale reveals his amazement at the fact the game's concept proved so popular that it reached its funding goal instantly. Toby is clearly very grateful to his fans and it's quite touching.
  • Toby Fox has a small message on the official tumblr blog about gaming responsibly
  • The official Undertale artbook has commentaries from Toby Fox and the artists that worked on the character designs and some of the commentaries are quite heartwarming. Toby originally was going to have Toriel be killed by the player, but as he wrote her dialogue, he felt completely shamed about killing her off and wanted to make it possible to get past her without having to kill her. From there, he made the game be possible to complete without having to kill a single person.
  • The "Winter" dialogue from the currently delayed Undertale alarm clock app reveals more lore during the cast's time on the holidays.
    • Papyrus held a Christmas party with his own... unique flair. While it got rowdy near the end, many of the characters came to appreciate the time they spent there.
      • Papyrus observed his brother sleeping on the couch by the end of the night, and tucked him in, despite Sans usually being the one to take care of his brother. Papyrus believes that, even if he never said it aloud, Sans must have been very happy to be able to celebrate the holidays with so many friends, and he can't even remember the last time he could see his brother so happy.
      • Sans, in turn, is proud of his brother for putting so much effort into celebrating with his friends.
      • Alphys enjoyed her time at the party with Undyne, singing karaoke and admiring how she looked with the Mew-Mew Earmuffs that she gave her.
      • Mettaton confronted Mad Mew Mew over concern over Napstablook, which unfortunately escalated into a fight when they took too much "ghost juice". When things settled down, Mettaton and Mew Mew looked on towards Undyne and Alphys, glad that they had each other and were happy together.
    • Flowey remembers staying in the Ruins, watching Toriel live alone. His sadistic nature had led to him looking down on her for how she had fallen, but while falling asleep on the floor, she touched Flowey's face and said:
      Toriel: Asriel... I'll never let you go again...
      • Toriel recalls knowing someone that would fill their glass all the way to the brim, being "the most efficient way to fill it"; which Asriel would then mimic, and naturally spill about. When she woke up from the floor of the Ruins, she found a glass just like that. Passed out after she got too rowdy at the Christmas carol karaoke, she once again woke up to a glass filled to the brim with water. It's heavily hinted to be from either Flowey or Asgore.
      • The very fact that Flowey's on the surface and still seems to care about his mother despite supposedly being "unable to feel love" shows that deep down, Asriel might still be in there somewhere.
      • Furthermore, when asked what kind of gift he would like for Christmas, Flowey states that he's too grown-up to want presents. He then goes on to give the specific example of "a red bike with a golden basket" as a gift that would be useless to him, with a coy smile.
      • Flowey then acknowledges that the reader's likely wondering about the ribbon he's wearing during the alarm clock dialogue, he deflects the question by saying "Who cares who gave it to me?" but vaguely hints it was Frisk who gave him the ribbon. Considering how none of the other characters reference Frisk in any matter, this heavily suggests Frisk is perfectly content sitting on the sidelines peacefully observing the hijinks of their new friends and family, who likely were not bringing them up in dialogue just to protect Frisk's privacy.
      • It's later revealed it's actually Papyrus who gave it to him, saying that he gave a matching red scarf to his friend who went missing later. That said, the fact that it's implied that the dialogue options are all directed at Frisk is heartwarming enough.
    • After Undyne's hockey game, Toriel served everyone a thermos of alphabet soup.
    • Asgore further recounts his old friend Rudy, following him from his youth to college and his twilight years, before he eventually "fell down". His favorite memories would include how they re-enacted Santa Claus and his reindeer, giving gifts to others in Snowdin. He laments that he was unable to show him the sun when the barrier was finally broken, but is glad to see that his daughters will not only get to see it, but grow up safe and happy in their now-hopeful world.
      • Hell, the very fact that the existence of the alarm clock shows that the Pacifist route is indeed the 'canon' ending, if there is one, as everyone's living happily on the surface with no worries about resets and timeline hijinks whatsoever.
    • Everyone gathers at a massive super-tree they've set up, passing around warm soup and preparing to sing carols. They're all just so glad to be celebrating a wonderful winter... even if the Christmas spirit is a bit unfitting for September.
  • As a form of Woolseyism, the official Japanese translation of the game makes the brotherly bonds between Sans and Papyrus all the more touching. Not only are Papyrus' reactions to Sans' goofy antics toned down to be less vitriolic, but rather than referring to Sans by a first name basis, Papyrus instead opts refer to him as "Nii-chan" (big bro). And Sans is just as supportive of an older brother as he is in the original translation.
  • Overlaps with Awesome Music, but the song Hopes and Dreams, which was inspired by Anamanaguchi, would eventually be covered by the same band that inspired it in 2021, bringing it full circle.

  • Throughout the game, you can encounter a Nice Cream salesman whose business is struggling because he can't find any customers. You can find someone willing to buy out his entire stock if you convince the pair of Royal Guards to get together.
  • The friendship between Papyrus and Undyne. At first, it seems like a classic Bad Boss/Frightened Subordinate sort of relationship, but they both genuinely love each other in a platonic way, and befriending them both leads to them having the same phone and joint phonecalls with you, complete with moments of heartwarming and funny! It's really adorable. In fact, if you fight Undyne in a run where Papyrus is dead, she coldly promises to kill you for murdering her friend.
  • Everything to do with Sans and Papyrus. While their dynamic is a source of many Funny Moments, when you dig further into the game and learn just how much they care about each other, it also becomes incredibly touching. Two goofy brothers, one lazy, the other obsessed with getting to the top, but despite their differences and constant bickering, it's plain as day that they love each other very deeply. The first thing Sans does after you meet both of them is describe at length the fact that Papyrus is such an unrelenting nerd that he's been wearing nothing but a homemade soldier costume for the last couple of weeks... and caps it off by saying, with total sincerity, that he thinks his brother is awesome. In the No Mercy ending, when you face Sans, his trademark grin never wavers, but his words and the unrelenting brutality of his attacks make it clear that killing his little brother was the worst thing you could possibly have done.
    • The fact that Toby was able to layer on just how utterly dedicated Sans is to his brother as thickly as he did while still retaining enough subtlety and balance to keep it from being unrealistic or annoyingly schmaltzy deserves a mention in and of itself.
    • Bearing the above in mind may ostensibly make their relationship seem a little one-sided, especially since Sans is literally the only person Papyrus isn't unrelentingly nice to, but looking at the nuances in their relationship make it clear that it's anything but: to begin with, the guy stresses how much he's looking out for Sans' best interests almost constantly - even if it's usually disguised as a complaint, Papyrus never wastes an opportunity to push his brother towards being productive and healthy, while still dutifully taking care of the responsibilities he lets slip through the cracks (like feeding his pet rock). And it doesn't go unnoticed either; Sans will more or less tell you in an optional piece of dialogue that Papyrus' nagging is the only thing keeping him from wasting away as a completely sedentary lump, which is especially poignant if you buy into the theory that Sans has depression. On top of that, Papyrus still spends plenty of phone calls happily recollecting activities the two of them shared, such as building snowmen and helping each other construct their sentry stations, and if you ever find yourself in a room with "outer spacey sci-fi stuff", Papyrus' reaction pretty much amounts to "OH, MY BROTHER WOULD LOVE THAT!" While a lot more subtle about it than Sans and his "isn't my brother cool?" routine, Papyrus still loves his annoying and lazy big brother just as much as he loves him.
      • Fridge Brilliance elevates Papyrus' often less-than-friendly attitude towards Sans into this: if you pay attention, it's very obvious that Papyrus is trying to play himself up with practically everybody he comes across, so much so that one of his battle texts literally reads "Papyrus is trying to play it cool". Even with Undyne, his closest and only non-related friend before you showed up, he still says and does things he doesn't actually mean to kiss up to her (e.g. liking grease, having a positive opinion about anime) because he doesn't want her to think less of him; it's very obvious and she sees right through him anyway, but still. Of all the people in the underground, Sans is the one and only person Papyrus isn't afraid to be completely emotionally honest with.
    • When Toriel and Sans finally come face-to-face in a True Pacifist run, it's established they've known each other for years but only by way of talking through a door. Neither knows the other's name or seen the others' face, and only recognize each other by their voices. In spite of this, Toriel recognizes Papyrus immediately and knows his name. Apparently Sans gushed about Papyrus extensively to Toriel in between telling bad jokes. Fridge Logic kicks in; telling Toriel his name? Who cares. Telling her how much he loves his brother? Far more important.
    • A kind of twisted piece of heartwarming comes from the Genocide Run. On a Pacifist or Neutral run, Sans often has a very teasing attitude towards Papyrus, telling him Junior Jumble (a word puzzle Papyrus has immense difficulty with) is for babies and poking fun at the fact that Papyrus won't activate the bridge trap. However, on a Genocide run, Sans's teasing completely stops. Instead, he says he should have put down Junior Jumble instead of a word search because it's way harder, and suggests Papyrus use the bridge trap on Undyne instead, saying she'd love it. Since you, the player, are being such a jerk, Sans plants himself firmly on Papyrus's side and tries to give him the support he needs.
  • Depending on your interpretation of Gaster, him starting to recreate himself can be this in the same way it is Nightmare Fuel and Awesome.
    • Especially since there's absolutely nothing about his creepy Easter eggs that indicates that he might have been in any way evil. To all appearances, he seems to have been a perfectly good monster and a good friendnote  of Sans's who just stumbled on something he shouldn't have.
  • Most major characters won't permit you to name yourself after them. However, Papyrus ("Papyru") is nice enough to let you do it, and Mettaton ("Mett(a)") thinks of it as free publicity. note  It turns out it's, in Asriel's words, "not the nicest person" you're naming after them, but still, thanks, guys.
  • Coming from Flowey of all people, but in the Undertale Q&A tumblr, Flowey seems to actually bother remembering what Papyrus' favorite food is. Given how he's usually like, it's a bit endearing to know that he takes the time to remember what Papyrus likes.
  • Flowey's Villainous Friendship with Chara in the Genocide Route stands out as weirdly kind of sweet compared to everything else in the route. Twisted as they've both become, we see a much different side of Flowey when he thinks he's been reunited with his old friend and looks forward to executing their plan and living together on the Surface. Creepy face notwithstanding, it's hinted that Chara has some lingering affection for him as well, even causing the bloodthirsty demon they'd become at the end of Genocide to actually hesitate to kill him when he'd outlived his usefulness and just given them more reason than ever to want revenge on him. (Of course, unless you reset, what happens next is... not as heartwarming.)

  • Toriel. Really, everything about her is heartwarming incarnate. She's a sweet old lady who only wants to guide you through the caverns and keep you totally safe.
    • The first thing she does is shoo Flowey away, tells you not to be afraid, and calls you "her child".
    • She guides you through the spike floor puzzle, because she decides it's too dangerous for you to do yourself.
    • When you encounter a training dummy what's the first thing she teaches you? Fight? No. Talk or find a way out of fighting without resorting to violence. She does it in a the same way a mother would teach a child that "fighting is wrong, hurting others is bad".
    • After she gives you a cell phone to keep contact with her, and you can call her "mom". At first she's a bit embarrassed, but she gladly accepts it if that's what would make you happy.
    • Finding a piece of the pie that Toriel baked for you on the floor after going to sleep in your room. She even turned the lights off for you.
    • That big hug she gives you if you spare her and convince her to part ways with you.
    • She gives you the easiest of the boss battles to introduce you to the battle system. You can still die, but she tries her best to not let it come to that. Even in the secret Hard Mode, where the enemies are much more overwhelming and even her attacks are significantly harder to dodge, she'll still refuse to kill you.
  • Cheering up Napstablook. It takes some effort, but they finally become happier. They even show you a trick where they make a hat out of their own tears!


  • It makes sense that Snowdin is the first location in the game. While every location is meant to evoke the Underground's lovely-yet-melancholy feel, Waterfall gives a beautiful tone and Hotland/The Core gives a badass tone. Snowdin, however, sets the game's "warm and fuzzy", adorable tone so well that (between the Christmas motif, the sweet Background Music, and it being the place that you see just how sweet everyone in the Underground is) it's Sweet Dreams Fuel.
  • Dogamy and Dogaressa are a Sickeningly Sweetheart Happily Married couple. How they act together is heartwarmingly funny. How each act if you kill the other is heartwarmingly tear-jerking.
  • The Greater Dog is an adorable little puppy in a hulking suit of armor. Sparing it requires you to pet and play with it like you would a real puppy. After sparing it, the dog (actually normal-sized out of the armor) hops out of the armor, licks you, then hops back in and walks away, its butt hanging cutely out of the armor.
  • Sans asking you to show yourself to Papyrus. He knows how determined his younger brother is to find at least one human and just seeing him happy is enough for Sans.
  • On your date with Papyrus, when he confesses he doesn't love you in a romantic sense, he tries his best not to upset you, promises he'll remain your (cool) friend and even though you won't find someone as great as him, he'll help you settle for second best. Speaking of him, it is literally impossible to offend him. If you attempt to insult him in battle, he'll take it as your attempt to make him feel better about fighting you. If after defeating him peacefully, you try being abusive, he interprets it as you berating yourself.
    Papyrus: (if you try to call him a "loser" after battle) HUH? WHY WOULD YOU... BERATE YOURSELF SO LOUDLY???
  • It's small, but one of your first plain-to-see indicators that the brothers have a great relationship despite their outward dynamic is Sans's last comment if you talk to him after the Electricity Maze scene. After telling you that Papyrus is dressed in a costume he's been wearing consistently for weeks since they made it for a party, what he says is:
    Sans: man. isn't my brother cool?
  • Regarding the fact that Santa apparently delivered the action figures to Papyrus: in Asgore's house near the end of the game, you can find a Santa Claus outfit in a dresser in his bedroom. This means that Asgore, the King of Monsters, takes some time out of his schedule to deliver presents to Papyrus, and presumably, the rest of the Underground, while dressed as Santa. Judging by the number of action figures Papyrus has, he's been doing this for a while.
    • Alternatively, one could assume that Sans is the one who dressed up as Santa, seeing as he's the one who has the thank-you note (and, conveniently enough, he's also "A CHUBBY, SMILING MAN WHO LOVES TO SURPRISE PEOPLE"). Or they worked together on it. Either way, someone truly cares for Papyrus despite him being the (non-obnoxiously) self-absorbed Cloud Cuckoo Lander he is.
  • If you cancel a No Mercy run at Papyrus, both he and Sans will deliver some heartwarming lines.
    Sans: "hey, i really respect what you did back there. thanks."
  • Papyrus...just Papyrus. For all he talks about capturing you in order to join the royal guard he will never bring himself to actually go through with it even when he easily could have. If you get down to only 1 HP he will immediately stop and bring you to his garage for you to rest (placing you in a very-easy-to-escape holding pen), and if you do happen to lose to him multiple times he'll just give the option of bypassing the fight in favor of letting you go/becoming your friend.
    • And if you are doing a No Mercy Run, Papyrus won't even fight you but instead say that he believes you have the potential to become a better person... even after you kill him! This skeleton is basically MERCY incarnate. And it works. On a meta level, he's the main reason many people turn back on their No Mercy runs.
    • Another meta example. What's Papyrus' greatest desire? To join the Royal Guard... namely, so everyone will respect, admire, and love him. For all his boasting, it quickly becomes clear that Papyrus desperately wants friendship and love above all else. And in the fandom... Papyrus is universally beloved. You'll be hard-pressed to find a fan that dislikes him, and most players rank him as one of their favorite characters, if not their absolute favorite. People love him for his showboating, his Adorkable personality, and his unrelenting kindness. So, in a way, Papyrus got what he always wanted, just by being himself.
  • You can meet a snowman, who wants to see the surface, but cannot move. You can obtain a piece of the snowman, and if you carry it to the surface, Sans will remark that "you made a snowman really happy."
  • If you try to stay at the inn but don't have 80 G, the innkeeper will say something like "Oh, you poor thing! I can't imagine what you've been through. There's an empty room upstairs, and you can stay for free."
  • In the Switch version of the game, you can find a secret boss fight that turns out to be the Mad Dummy possessing a Mew Mew doll from Alphys’ lab. The best part? You can actually spare the dummy this time- perhaps one of the few characters who is truly evil finally gets a happy ending!


  • On any run in which you spare Papyrus, Sans will appear at the entrance to Waterfall and ask if you want to go to Grillby's. If you say yes, he spends the meal talking about Papyrus and mentions a talking flower. He then asks if you'll foot the bill, which is "only 10000G" which the player probably does not have. He then says he's kidding and asks Grillby to put it all on his tab. D'aw, Sans, you do care.
    • When talking about the talking flower, we know Papyrus has been talking to Flowey, but Sans assumes it's someone using an Echo Flower to play a trick on him, and asks you to "keep an eye out." Sans enlisting his brother's new friend to find out who's tricking him is a small detail, and only a fraction of Sans' Big Brother Instinct, but it's still quite sweet.
  • Shyren. She's a unique encounter who's ashamed of her singing and scary face and fights with her back turned to the player. However, if you were to hum to her, she follows your lead, being comfortable singing along. You can then spare her. However, if you were to keep humming, the music you both make attracts a crowd of monsters. Hum again, and it becomes a full blown concert complete with Sans selling tickets made of toilet paper. Keep humming, the tickets are sold out and the monsters throw articles of clothing onto the stage. It's socks. Scandalous! After humming a couple more times, the weight of stardom starts to wear the two of you down, and Shyren begins to think about her future. You and her then decide it's time to go on your own journeys, and after a farewell song, you go your separate ways.
    • In the epilogue, Shyren forms a musical band with Napstablook, Mettaton and Burgerpants, having found her calling at last. And what's more, her meeting with you is a memory she'll never forget. She releases a hit single which is about her parting with the player!
    • And the player never forgot either! Later in the game when encountering Knight Knight, you can put her to sleep by singing. And if you went on the music tour with Shyren? You sing Shyren's song, which puts Knight Knight to sleep faster and is one heartwarming Continuity Nod.
    • Sans selling the tickets only happens if you've spared Papyrus, since Sans disappears from the game until the judgement hall otherwise, suggesting that sparing Papyrus is enough to convince Sans (for the most part) that you mean no harm.
  • While befriending Undyne is primarily hilarious, her comments about not wanting to put Papyrus into harm's way because he's too nice for battle are surprisingly endearing. And, as you find during a No Mercy run, completely correct.
    • If you kill Papyrus before meeting Undyne in a Neutral route, she laments about this during her O.O.C. Is Serious Business intro before her battle.
      Undyne: Papyrus, who I have trained every day... Even though I KNOW he's too goofy to ever hurt anyone...
  • Speaking of befriending Undyne, when you purposefully hit her with an absurdly weak attack, she tells you that you remind her of Asgore, her mentor. And she drops her weapon, because she doesn't want to fight you either!note 
    * You pretend to swing at UNDYNE with all your might.
    (The attacking sound is heard, the screen fades to white, then goes back to normal and you hear the usual hit bang...but you take off only 1 HP.)
    Undyne: What. That's the best you can manage? Even attacking at full force... You just can't muster any intent to hurt me, huh? ... Heh, you know what? (She puts her spear down.) I don't actually want to hurt you either. At first, I hated your stupid saccharine schtick, but... The way you hit me right now, it... Reminded me of someone I used to train with. Now I know you aren't just some wimpy loser. (She grins happily.) You're a wimpy loser with a big heart! Just like him...
  • If you befriend Undyne and end up resetting the game, while she's giving her bombastic speech before her fight she adds in the comment that she feels like she knows you and gives you a genuine smile.
    Undyne: The whole time I was chasing after you... I felt something... Strange. The echoes of something warm, something... Something like "I miss being friends with you."
  • Worth noting is that, the worse of a person you are to Monster Kid, the more heroic of a character Undyne is revealed to be. If you run off-screen when they fall from the bridge, you hear dialogue from the next room of Undyne saving Monster Kid, who insists that you were probably just running to get help. If you're able to muster the coldness to just stand and let Monster Kid fall, you get a rather awe-inspiring moment where Undyne stops in shock, then leaps down from the bridge to save them. Not only does she manage get to Monster Kid in time, she then continues onward to fight you anyways, despite being injured from the fall. If you are playing on a Genocide Route, Undyne saves Monster Kid by leaping in front of them and using her own body to shield them from your lethal blow.
    • On a Pacifist route after befriending Undyne, if you call her while at this location she'll reveal that, despite how dead set she was on killing you during the chase, at that moment, the only thing she was thinking of was how to save Monster Kid, and was worried you'd attack them while she was vulnerable.
    • Inversely, if you're good person to Monster Kid, and rescue them when Undyne is right in front of you, Monster Kid will stand up against Undyne to protect you, causing her to back away and them decide to be your friend instead of enemy.
  • Monster Kid themself is a very heartwarming character. During a bit of the Waterfall segment, they're always by your side, being friendly to you and helping you progress by boosting you up a ledge. As annoying as some players can find then to be, they are still an adorable character.
  • At the end of the battle with Undyne, when her armor is overheating to the point of rendering her unconscious (and quite possibly dead momentarily), the player can choose to have Frisk save her by pouring water on her gills. Given how absolutely hell-bent the girl was on killing Frisk (who, on Pacifist runs and by default, is an innocent child), this really speaks wonders.
    • If you choose not to save Undyne, it's implied that she's rescued by SANS, of all people. (Returning to the bridge reveals that both she and Sans are gone. And if you visit her house, Papyrus tells you that she's sick with heat stroke, and that "someone else must have taken her home, because she can barely move.") He may annoy her with his laziness, but he steps in to save her when she needs it most.
    • Equally heartwarming, when Undyne is sick, you find Papyrus waiting patiently outside her door in case she needs anything.
    • The reason why Undyne was so hellbent on killing Frisk and taking their soul counts too. She isn't driven to kill a kid for shits and giggles. But rather, Undyne truly cares about all her friends along with all of monster kind, so of course she would be DETERMINED to capture the piece needed for everyone to finally break free from the underground.
  • Paying for the Temmie's college education. The player had no real reason to do it, but it's sweet regardless.
    Temmie: WOA!! thas ALOT o muns... can tem realy acepts... OKs!!!! tem go to colleg and make u prouds!!!
    • ... And she comes back wearing the most adorable little mortarboard cap and sells one of the best armors in the game.
  • Scattered throughout the Waterfall area are "Echo Flowers", which repeat back the last thing that was said near them. As you make your way through the area, you can listen in to snippets of a conversation between two people. One keeps pressing the other to tell them their wish, which they're too embarrassed to say. Eventually after one of them promises not to laugh no matter how silly it is, the other relents - their wish is to one day leave the underground, and stand on top of Mount Ebott looking up at the stars with their friend. The other laughs, which initially makes them mad, but they admit they couldn't help it because that was their exact same wish.


  • Minor example, but when Mettaton asks "WOULD YOU SMOOCH A GHOST?" it could be interpreted that Mettaton was trying to find a date for his cousin, Napstablook.
  • Alphys helping you with part of Mettaton's encounter in a Pacifist run by sneakily showing you the answers to his questions comes off as surprisingly touching. The only other monsters to be so openly helpful at this point are Sans and Monster Kid (though Papyrus does try).
  • While pretty much all the Boss Fights in a Pacifist Run count to some extent, the one against Mettaton takes the cake — Napstablook is the first one to call in to compliment him and express disappointment that it's Mettaton's last show.
    Mettaton: Hi, you're on TV! What do you have to say on this, our last show???
    Napstablook: .....oh........ hi... mettaton... i really liked watching your show... my life is pretty boring... but... seeing you on the screen... brought excitement to my life... vicariously[.] i can't tell but... i'm guessing this is the last episode...? i'll miss you... mettaton...... ... oh.... i didn't mean to talk so long... oh..........
    Mettaton: No, wait! Wait, Bl... H... they already hung up...
    • What really seals the deal, however, is if the player found the use for the Mystery Key sold by Bratty and Catty. It unlocks the house next to Napstablook — Mettaton's actually their cousin, and hearing Blook quietly apologize for talking so long before hanging up evokes a moment of revelation. Mettaton attempts to pass off the call as an Ignored Epiphany. Then he's inundated with callers begging him not to stop the show — and given that his dream had always been to be a star...
      • Once you know the deal with Alphys and Mettaton (that they're working together to make Alphys look better), it's actually really sweet to see the lengths Mettaton goes to to keep the show going — even if part of it was to play to his ego, he was willing to play the bad guy so Alphys could be the hero. On another note, Alphys's genuine distress when she sees Mettaton all beaten up, and her relief at seeing he's still alive, can give fuzzy feelings to anyone's heart. Though their relationship may be strained, it's touching to see how much Alphys values Mettaton's friendship. In the face of her other experiments that really contributes her crippling self-esteem that culminates into suicidal thoughts, it is important to note that Mettaton is an experiment of hers that actually ended well and what this must mean to her.
      • Another touching thing is visible as soon as you can freely explore Alphys' lab. Examine the Mettaton poster, and written on this one in particular is a message on the order of 'thanks for making my dream come true' or something along those lines. This refers to Alphys making a robot shell for Mettaton the ghost, allowing him to become a star.
      • During the True Lab portion in the Pacifist route, Alphys will mention at one point that she is very scared to be left alone or forgotten by Mettaton. Yet, if Mettaton survives a playthrough that Toriel, Undyne, and implicitly Alphys don't, he will prove that her fears are unfounded as he will look for her and make a statue in her resemblance.
      • Like Undyne, Mettaton trying to kill the character might leave a bad taste in anyone's mouth, but the reason why he is determined to do so is opposite to Undyne's but still has a valid point: he doesn't want to endanger his own people for an impending war that they will surely lose.
  • It's very minor, but if you go back a tiny bit after Mettaton's play, you meet a nervous looking lion who notes that Mettaton looked "really cool" in his dress, and and that "it sort of makes [him] feel like [he] could wear one too!" If you backtrack again during the playable epilogue, you can meet him again and he actually is wearing one! For bonus points, if you talk to him he mentions that he was one of the people who called in to Mettaton's show and Mettaton recognized him and gave the lion his dress.
  • Killing Mettaton also reveals a bit more information on the kind of person he was behind his Troll and Killer Robot facade. If you explore the area more after the boss battle, his employees talk about how great of an employer he was to you and express worry that he is missing or "retiring". Aside from (apparently?) Burgerpants, he treats everyone kindly.
  • Alphys and Undyne in general make a surprisingly sweet couple. A lot of their interactions with each other just radiate Ship Tease.
    • Calling Undyne near the Waterfall has her reveal that's where she met Alphys, who apparently was looking "contemplative" and heavily implied to have been considering suicide as a result of what happened to the Amalgamates. According to Undyne, she asked Alphys what she thought was in the Abyss below, causing the latter to blush and explain her theories for several hours. Not only did the Hot-Blooded Undyne stay and listen for the entire duration, she was completely captivated by everything Alphys said. Basically, Undyne very likely saved Alphys from committing suicide, simply with a little time and kindness.
    • The entirety of the date with Alphys. It starts when Undyne asks you to deliver what's eventually revealed to be a love letter to Alphys. However, Alphys mistook the author of the letter as Frisk, and agrees to the date just to make up for manipulating them earlier. The date then consists of Alphys admitting she likes Undyne, you helping her gain the confidence to admit some of the things she's been hiding, and ultimately, Undyne not caring that Alphys lied to her in an attempt to seem cooler. Undyne then promises to help Alphys with her self-confidence, then afterwards thanks Frisk for looking out for Alphys.
      • It's easy to miss it, but if you tell Undyne that yes, anime is NOT real, she'll freak out... for all of two seconds. Because she has to stay strong for Alphys. She then thanks you for being honest with her about it.
      • Before the date with Alphys begins, she tries to give you gifts to improve the outcome, but quickly realizes none of them would be of any help to you. The gifts in question are: metal armor polish, waterproof cream for scales, and a magical spear repair kit—all of which would be perfect for Undyne!
      • Also at the very end of the date Undyne says she'll help Alphys believe in herself again. Alphys thinks this means Undyne will train her herself but Undyne gets Papyrus to do it instead. Undyne plays it cool but she not only recruits her best friend but the one person she knows never doubts themselves or anyone else. She probably knew Papyrus would be better at it then her. And it's sweet that Papyrus happily agrees. Giving Alphys a whole load of people who believe in her.
    • Pretty much any time Alphys is mentioned to Undyne or vice versa, it's completely obvious they're in love with each other.
    • When Mettaton asks you who Alphys has a crush on during his quiz, selecting Undyne will cause Alphys to hide her face and blush profusely, which is far more noticeable in a game where every character is shown in black and white. Mettaton proceeds to point out how obvious her crush is and notes that Alphys scrawls Undyne's name in the margins of her papers, names programming variables after her, and writes fanfiction of them sharing a domestic life together.
    • After the date, Papyrus specifically asks you to go check on Alphys, and it's obvious that, reading between the lines, he's really worried about her.
  • On a No Mercy run, when you confront Mettaton, he gives a variation on his usual Glory Hound speech from the Pacifist / Neutral route, saying that he needs to defend humanity because otherwise he'll have no audience... then says that "besides... there are some people... I want to protect." And if you blow the run by failing to meet the Hotland/Core kill requirement before the encounter, he'll have enough time before he dies to more candidly say that he's dying at ease knowing that you're not going to hurt Alphys.
  • In the Playable Epilogue, Undyne tells you to tell Napstablook she said hi. It's heartwarming to remember that Undyne, as Napstablook's neighbour, actually noticed and remembered them.
  • If you hold out long enough in the battle against Muffet, the spiders from the Ruins will send Muffet a telegram telling her that you're harmless to spiders, even if you didn't buy anything. If you manage to grind enough money to buy something from the Hotland bake sale, Muffet will immediately dismiss what she was told about you, reasoning that no-one so generous would be as cruel as she was told.
  • If you end the battle with Mettaton EX peacefully, Alphys is VERY relieved to learn that Mettaton has only run out of battery power.
  • The fact that Bratty and Catty seem to genuinely like Alphys and view her as something of a big sister figure, telling you about when they all lived on the same street and Alphys would take them on trips to the garbage dump. They both seem a bit sad when they note that they haven't really seen Alphys since she became the Royal Scientist.
  • If you call Undyne and Papyrus when entering the CORE, they will tell you that since the phone won't work past that point, they will stay with you in spirit, and they won't say goodbye just yet. Also doubles as a Tear Jerker.
  • On a non-Genocide run, if you buy something at the MTT Resort and make conversation with Burgerpants, he'll refer to you as his "Little Buddy."

    Final Area and Endings 

Neutral Ending

  • When you find the last 2 pieces of equipment in New Home, their names and descriptions say a lot about how Frisk (not Chara) percieves them. They are named the Heart Locket and the Worn Dagger. Frisk sees that it was special to someone by making note of the fact that it says "Best Friends Forever" and sees the dagger not as a weapon, but just as a humble vine cutter. The latter is especially meaningful in a Pacifist Run where they are so against the idea of violence that even when finding a knife (the same one that on the Genocide Run has truly terrifying power), Frisk can't imagine using it to hurt a monster.
  • As tragic as the circumstances are, meeting Asgore is kind of heart-warming. He's been built up as this scary threat the whole game, and you meet him in a field of flowers and he even attempts awkward small talk. Considering what he's been through, you kind of want to give him a hug.
    • Even when Asgore is described as a threat, it's only in reference to the fact that the only method of breaking the barrier requires that he gets a hold of a human's soul. Everyone completely agrees on Asgore being kind, friendly, "fluffy", funny and harmless. Undyne even mentions - should the player be on the run for the Pacifist Ending - that he couldn't hurt a fly. The fact that everyone loves the king is heartwarming in and off itself and makes the fact that they weren't lying and he is just as nice and friendly to Frisk as described, even if sad, very heartbreaking.
      Asgore: Nice day today, huh? Birds are singing, flowers are blooming... Perfect weather for a game of catch.
      • One of the stand-out examples of characters praising Asgore comes from Papyrus, after his battle on the Neutral and Pacifist routes. He specifically calls Asgore "a big fuzzy pushover," and goes on to say that if the player simply asked Asgore to help them out of the Underground, he would immediately do it. The last bit in particular makes Asgore's fight even more depressing.
    • Before you meet him, you wander through his house, and find a note he left for anyone who might come by, explaining that he's in the garden, but if you want to talk to him, you can just grab the keys and join him. Yes, the king of all monsters is so nice and loving towards his subjects, he encourages any one of them to simply come by for a chat, or to get something off their chest, any time they want.
    • As you make your way to the garden, the beautiful track "Undertale" plays, as various monsters appear to explain the story of Asriel and the Fallen Child. It's heartbreaking, but still sweet, since you can see how much the monsters really loved them. And since they seem to think you're a monster, even their talk about how the final human soul will break the barrier is heartwarming in a bittersweet way, since they don't realize you're the human in question. They're genuinely trying to be encouraging and hopeful, since they believe freedom is coming.
      Aren't you excited? Aren't you happy? You're going to be free.
  • After defeating Asgore, he encourages you to take his life so that you can use his soul to leave the Underworld. However, if you choose to spare him (defeating him is the only way you get that chance, since he takes away the Mercy option at the start of the fight), he'll be so moved and surprised by how you're willing to sacrifice your freedom just to avoid killing him, that he offers to redeem himself by calling off his war against humanity and states his plan to repair his relationship with Toriel, so both he and Toriel can both raise you as their own... and then Flowey kills him.
  • To the south of The Barrier is a room with seven coffins, each labeled with a picture of the SOUL of the human within. Asgore had the decency to give his adopted child and the rest of the fallen humans dignified funerals.
    • If you return there in the Pacifist ending, you'll see that they are open, meaning that he must have decided to take the bodies of the previous humans to the surface instead of abandoning them to stay underground.
  • At the end of the last battle in the neutral path, when Flowey is about to kill you for good, the six human souls completely break free from Flowey's control and defeat him. Also counts as a moment of awesome.
    • Even before that specific scene, the souls are helping you during the fight with Flowey. When he calls each of the souls out to attack you, you can approach the ACT button and call for help... and the attacks suddenly stop. A different soul appears at the top and all of the weapons turn into healing items. Even with the soul who had the Notebook, the words of malice and negativity turn into hopeful healing words after Act is approached.
  • In the neutral ending where Papyrus is the only surviving boss, Sans is pretty much outright stated to be working his ass off keeping the country in line through paperwork and the like just so Papyrus can think he's a good king, and keep being his beloved self to the people of the Underground.
  • In the ending where Mettaton is put in charge of the Underground, Alphys has gone missing. Discussing this is the only time Mettaton's smug cheeriness wavers during this ending, and he reveals he was hoping she could help him rule, and admits he was a jerk towards her and just wanted to apologize. He's erected a statue of her in his Egopolis. Mettaton's a crappy king, a mixed bag as a friend, and a questionable person... but he does care.
  • In several neutral endings, one of Sans's lines is as follows:
    Sans: so, uh, hey... if we're not giving up down here... don't give up where you are, ok?
    • The best possible neutral ending, which contains the above line, is a Bittersweet Ending, but it does have its moments. Monsters are demoralized by what happened, but still hold out hope of seeing the surface, without the lust for vengeance they have if the player killed some of them. If you befriended Undyne and didn't kill anyone, she doesn't blame you for Asgore's death.
    • Hell, a lot of what Undyne says in the best neutral ending, from assuring you that what happened to Asgore wasn't your fault to this line:
      Undyne: Hey, where-ever you are... I hope it's better than here. It took a lot of sacrifice for you to get there. So, where-ever you are... you have to try to be happy, okay!? For our sakes! We'll feel better knowing our trouble was worth it. We're all with you! Everyone is! Even the queen!

Pacifist Ending

  • You'll know you're on the True Pacifist route when Toriel shows up to intervene when the fight with Asgore is about to start. She says that every creature deserves mercy — even if she personally is not ready to befriend the person you were just facing.
    • During the credits, it shows Asgore trimming a bush of Papyrus in front of Toriel's school, which could mean that the two are slowly trying to become "friends" again.
    • A subtle one is added onto this. During the battle with Papyrus, he says a multitude of things that one can write off. Undyne liking him, him becoming captain of the Royal Guard, the king trimming a hedge in the shape of his smile, and having friends. In the end, Papyrus gets everything he ever wanted. Well, except for becoming captain of the guard.
    • After spending the entire game unable to call Toriel because a dog stole her cell phone, Toriel will learn how to text message you. Most of the messages go from silly to ridiculously sweet and heartwarming.
  • Forgiving and embracing Asriel when he feels he doesn't deserve a damn thing and is absolutely awful and worthless. It's made better by the fact that it's a legitimate choice of the player to do this--you're still given the options to not forgive or comfort himnote , which makes the emotional impact of doing so much stronger than it would be if the player was forced to via a cutscene or But Thou Must!.
  • Going to sleep in the True Lab. One of the amalgamations finds you, looms over you, reaches out... tucks you in, pats you on the head, and vanishes. Considering that none of the Amalgamates are actually malicious, it's likely that they're just trying to be courteous to their guest.
    • Appeasing Endogeny by petting and playing with it, at which point the music will change to the old and familiar tune of Dogsong. Despite its monstrous form, despite everything, it's still just a dog.
    • While there, the player can stumble on a room with VHS tapes. Watching them reveals that they're actually home movies from Toriel's and Asgore's married life. The first has them eagerly awaiting Asriel's birth, while the rest involve Asriel's friendship with the Fallen Child.
      • Although the tapes have some pretty horrifying implications (namely, that the Fallen Child deliberately poisoned themself in order for them to fuse with Asriel and kill six humans), they still manage to have another heartwarming moment when one of the tapes is revealed to be a recording of Toriel, Asgore, and Asriel at the dying Child's bedside, begging them not to give up. Toriel and Asgore's utter devotion to their adopted child is as beautiful as it is utterly heartbreaking.
    • During the epilogue you can walk back through the different towns and find the freed Amalgamations, having gone back to their families. Lemon Bread is happy to be back with their sister Shyren. Endogeny turns out to be the parents of all the dogs from Snowdin mixed together and their pups don't seems to mind, they're just happy to have their parents back. Snowdrake's mother goes back to live with her son and husband, who have reconciled with each other.
    • One of Alphys's diary entries reveals that Asgore left her five messages. Four of which were about how angry everyone was with her. One of which was about a cute teacup he found that resembled her profile. Asgore remains genuinely nice to Alphys and doesn't blame her for the experiment going awry.
    • If you accept the theory that Chara only turns bad on a No Mercy run, the flavor text for the bathtub after you've gotten the key from it—"It's just an empty bathtub."—can be seen as Chara trying to reassure Frisk that there's nothing to be afraid of in it.
  • On a Pacifist run, the part of the castle that looks like Toriel's home has a mirror. At the start of the game you can examine the mirror in Toriel's house to the response of "It's you", this mirror gives it a small Call-Back, "Despite everything, it's still you", a touching confirmation that you refused to let the underground steal your kindness. And in the Playable Epilogue, checking mirrors will result in the message "Still just you, Frisk."
    • This is even more heartwarming if you consider the alternative. On a No Mercy run, examining the mirror instead results in, "It's me, (character name)." — indicating how Frisk is being taken over by the Fallen Child. But if you reach New Home as a pacifist, then in spite of everything, you're still you.
    • If you take into account the Narrator Chara theory, this could also be seen as them astonished at your DETERMINATION to do the right thing, even in the face of adversity. You refused to let the Underground change you, and in doing so, proved that it isn't kill or be killed.
    • If this simple statement is heartwarming, then what about Sans' judgment on a Pacifist run? After explaining the true nature of LOVE (Levels of Violence), he says something similar to the above mirror quote, that you refused to hurt others to distance yourself from the pain you felt during your travels, that your kindness has instead earned you the friendship and love of the monsters. He outlines the Sadistic Choice before you, with your life and the fate of the Underground depending on your decision, and basically admits he doesn't have an answer for it... but he fully trusts you to make the right choice. The ethereal music playing during this scene sells it; it's a completely different kind of triumph from what you feel after hacking your way through a standard RPG boss.
      Sans: you never gained LOVE, but you gained love.
  • The final boss of a True Pacifist run is full of much needed, and absolutely praise-worthy, DETERMINATION!
  • Gerson, the shopkeeper in Waterfall, tells you to come back later for the story about why Asgore is named "King Fluffybuns". If you come back during the epilogue, he explains it involves an incident in a public address long ago in which Toriel accidentally called him by his pet name while a microphone was still on, and Asgore decided to roll with it.
  • And then there's the buildup for the Pacifist Run ending - it initially plays out like the Neutral, until Toriel comes in to berate Asgore, followed closely by Undyne, then every other major character you've befriended along the way, all of whom are trying to stop the fight. The look on Toriel's face as each person appears is especially heartwarming as she realizes the human has made so many friends, she joyfully asks each one if they are your friend. It all comes with an equally heartwarming reprise of Fallen Down.
  • The end of the True Pacifist run boss fight is a mixture of this and a Crowning Moment of Awesome. Flowey has absorbed the SOUL of pretty much everyone in the Underground, including all your friends, turning into the boss Asriel Dreemurr. Asriel batters the player's SOUL to within an inch of their life, and all the while you struggle against him, "Nothing happened." It seems hopeless. The game acknowledges you can't SAVE your game anymore, but...
    But... Maybe, with what little power you have...
    You can SAVE something else.
    • This leads to a touching sequence where the game replaces your ACT button with a glowing SAVE button—using it causes you to reach into Asriel's soul and find your friends' souls in there. You discover they've lapsed back into their previous patterns of hopelessness, becoming faceless Lost Souls. You have to SAVE them by showing them that you are their friend, that you care about them and remember important things about each of them. This brings back their positive memories and returns them to their true selves, complete with an outburst of support for you. It's hard not to be inspired by doing this while "Hopes and Dreams" and "Save the World" play in the background.
      "Well, some humans are OK, I guess!" (Undyne)
      "No, that's not true! My friends like me! And I like you, too!" (Alphys)
      "nah, i'm rootin for ya, kid." (Sans)
      "Your fate is up to you now!" (Toriel)
      "You are our future!" (Asgore)
    • When trying to SAVE your friends, you have to fight them, one last time. Each hit only takes off 1 HP, meaning you'd have to be actively trying to die by any of them. Why is this heartwarming? It implies that, even without their memories, even while trapped in Asriel's SOUL, your friends simply cannot bring themselves to properly hurt you. They love you too much.
  • Speaking of getting to SAVE your friends, the final option in the SAVE button that remains (after you've SAVEd everyone you've met along your journey) reads, "Someone else." Selecting this will trigger a cutscene that shows the memory of Asriel meeting the Fallen Child. Only after the memory is brought up will you have the option to SAVE "Asriel Dreemurr." But neither Frisk nor the player have any memories they can use to SAVE Asriel, so who supplied that memory? That's right: Chara. Seems that "someone else" doesn't only apply to Asriel; you can SAVE Chara as well.
  • Alongside the 'main' group of friends, eight other monster show up on screen to encourage you while you're trapped: Monster Kid, a Vulkin, Shyren, Snowdrake, Muffet, RG 01, a Froggit, and Greater Dog. These are all monsters that you help/encourage in some way, and now they're back to return the favor.
    • Finally, even though the game asks you to SAVE your friends, it's not done yet... one more person still needs to be SAVED. Asriel. He resists and keeps trying to fight, begging you in tears to let him win so that you don't have to leave him again. He still tries with a gigantic rainbow laser that wears your SOUL down to a tiny fraction of a hit point that takes away all your other options...except the one that's already glowing rainbow colors. In the end, you SAVE the one who needed it the most.
    • And finally, the player's heart refuses to break because it's too full of DETERMINATION to leave all of their friends to an abominable death.
    • As a testament to how much the game plans for, even in this ending—what's one way to SAVE Sans and Papyrus? Just be unceasingly kind to one of them. Even without any ACT choices directed at them, seeing someone treat either brother with the same care the other one does is so touching that it's enough to break them out of their hopelessness.
    • After the battle is finally over and Asriel is subdued you have the option to forgive and comfort him. The second option in particular allows you to hug him, something anyone would like to do after knowing and understanding all crap he's been put through.
  • Walking through the abandoned city at the end and seeing all the buildings, and having all the monsters tell you what Asriel meant to them makes you wish you could give up your soul for him.
  • In the True Pacifist run, the revelation of Sans and Toriel's past interactions, how they met, their mutual love of puns (revealed in her diary early on), his promise to her and their meet up at the end (as well as the heavy Ship Tease), is extremely endearing.
  • In the Pacifist Playable Epilogue, if you have access, go to the Secret room behind Sans' and Papyrus' house, it shows that Sans has a picture of himself with people you don't know... and a picture of you, your friends, and himself, and he's happy here too.
  • The aforementioned Playable Epilogue, in general. Worth the trip just to see everyone happy at last, even the mooks.
  • Really, seeing all the main characters interact and chat is very sweet. Even if they didn’t know each other before, they still befriend each other extremely quickly. Special mention goes to Alphys. After being so anxious, shy, and fearing everyone would hate her, everyone gets along with her well. She also stutters a lot less, and is more jokey and a lot more relaxed. She’s definitely starting to come out of her shell and while her insecurities might always be around, everyone is there to support one another.
    • The very first Froggit you can talk to gives you advice on sparing monsters, and implores you to be merciful if a monster does not want to fight. Talking to it again in the epilogue gives you this:
      Ribbit, ribbit.
      (Excuse me, human.)
      (You seem like you have grown into a thoughtful and conscientious person.)
      (Whether that was from my advice or not...)
      (I'm quite proud.)
  • Alphys's appearance in the credits. She finally gets that kiss from Undyne that she wanted! Alphys's reaction is also one of the funniest moments in the entire game.
  • If you head all the way back to the Ruins to talk to Asriel in the playable epilogue, you'll find that he's in the very first area where you started your journey before telling you the story of the Fallen Child, who hated humanity. He then tells you that he's staying behind, as showing himself will just make the others unhappy. If you continue to speak to him after this, he gives you an ironic echo.
    Asriel: Frisk... Don't you have anything better to do?
  • From the short scenes we see during the cast credits, it seems that monsters and humans are getting along just fine after the True Pacifist ending. In a Twitter post about any potential Fridge Horror stemming from Monsters and Humans re-uniting, Toby himself said that Fantastic Racism will naturally exist, but it would be very minimal, the happy ending is to be taken completely at face value.
  • Your last choice on the True Pacifist route is a prompt from Toriel. If you choose to stay with her, there's one last post-credits scene where she sneaks into your new room while you're asleep to leave you a slice of pie, looking at you adoringly before closing the door again.
  • Upon starting the game up after completing a True Pacifist run, Flowey appears. He says that the only threat remaining is you (as in the Player), as you have the power to erase the happy ending you had achieved and set everything back to the way it was when you first started the game, including the erasure of everyone's memories. Flowey does not want you to go through with this. After the sheer dickery and sociopathy Flowey exhibited over the course of the game, this is surprisingly humanizing of him. Of course, you can always respond to this by doing another True Pacifist run (and/or never doing No Mercy), which is what many have decided to do.
    • Especially for those of who need to find a way to bring Asriel and his parents together before the end. No matter how much he doesn't want to.
    • Flowey begging to have his memories reset as well. On one hand this could be interpreted as him asking to not remember that you were so cruel to throw everything away. On the other hand, it may be seen as a Heroic Sacrifice: since the Flowey driven with madness and the desire to have all souls is what made the True Pacifist ending possible to begin with, he is aware that he needs to forget everything so you have a chance of redoing it. Despite everything that he is and did and despite you being cruel in your desire to replay the game, he is the very person that hopes that you will use the replay for good and is willing to give up his memories to grant you the opportunity to do so.
  • During your final battle with Asriel, it's possible to find healing items called "Dreams". If you take a closer look at them afterward, it's revealed that a "Dream" is The goal of Determination.
  • While (pre-game) Chara's intentions are never precisely spelled out, a valid interpretation is that they poisoned themself in a sincere attempt to free the monsters from their imprisonment because the Dreemurrs showed them such kindness and love and they wanted to return that love by freeing everybody. Sure, Chara may not have been "the best person" and may have "hated humanity", but in many ways it's more heartwarming for someone who is so flawed to make a selfless sacrifice for their friends as it is someone who's flawlessly heroic.

Genocide Run

  • As dark and twisted and sad as it is, Flowey in the Genocide run says that his first instinct on waking up as a flower was staying with his parents desperately trying to care and feel something for them. Anything. Players who actually struggle with low empathy relate to that far more than "if you have no empathy you're just evil".
    • For that matter, Asgore found Flowey confused and scared. What did he do? Hug the flower and assure him it will be all right. Keep in mind that he very possibly had no idea who Flowey was - Flowey never clarifies if he reveals his identity - and it very well may be how Flowey got this name as Asgore is LONG established to be terrible at naming things.
  • During the fight with Sans, he offers you a chance to stop the fighting. Accept his offer, and he...proceeds to kill you with an unavoidable attack. While this appears cruel at first glance, and rightfully so considering you killed just about everyone in the Underground, there's more to it than that. A common interpretation is that he's appealing not to the player specifically, but to Frisk, the character you control. All he wants is to get through to his buddy and convince them to start all of this over again. And when he says "get dunked on" after killing you afterward? That's Sans going back to his usual jokey self, content that he got through to Frisk.
  • When you encounter Asgore in a No Mercy run, he's saying to himself that he's never seen a plant cry before. When he turns to you, he says that you "must be the one that flower just warned me about". YMMV on why Flowey does this, and it probably does have a large part to do with his own fear of Chara at this point, but the fact that he even tries to warn his father at all, implying either he wants his father to escape or that, despite everything he's been through, he still runs to his father in his moment of need, is rather heartwarming. Additionally, when Flowey kills Asgore and then destroys his soul in that ending, it's easy to see it as him giving Asgore a quick painless death and then keeping you from claiming his soul.
  • In a twisted way, even the end of the No Mercy run has a bit of a heartwarming moment if taken in a certain light: after an entire game of characters beating you over the head with how much of a monster (as in "bad person" not "race in Undertale") you are for going for 100% completion in a video game (and how terrible that makes a lot of people feel), finally the last person you see validates your playstyle and (if you choose to ERASE) shows you a small bit of kindness by calling you a "great partner" and wanting to "move onto the next world" with you. Even the largest monster in the game (aka the Genocide player) still ends up with a friend.