#<- yknow. because sans and papyrus are from deltarune

[abandoned-quiche]

[o-sunny-day]

WE AINT MAKIN IT OUT OF THE ROOMMATE TORIEL NEUTRAL ENDINGS WITH THES ONES 😭😭😭

AUUUGH WHY DO AMVS HAVE TO TAKE SO LONG TO MAKE anywho,

casually obsessed with an actively grieving man who hides all of it deep within himself, staying with a woman who has known grief all her life.

Okay ill explain about the songs I gave a bit more, I mean- if you’re really that interested

oh and also *pulls out secret box* theres more

and I have like 30 others- but I mean…. you don’t want that, do you?………………but by chance…..some MIRACLE…..anyone wants………my………i mean……..my dms are open…………..I also like other neutral runs yk……..and like………yknow……….Undertale………

FRANCIS FOREVER!!!! This ones pretty self explanatory if you listen/you’ve listened to it before.

Not being who you want to be cause your other half isnt there, not being able to sleep, “I miss you more than anything” THE WHOLE SHEBANG!!!

Yk I actually made an animation inspired off of a certain part in the amv I have in my head for this song- But I used “Sailor Song” instead because……..I actually don’t know why, come to think of it-

BUT BASICALLY the line “I look up at the gaps of sunlight” before “I miss you more than anything” HURTS, yes, but ALSO

Sans cant exactly be looking up at….the sky cause uh…..underground. So he’s looking at the hole that you fall from!

THE ONLY THING!!!! This one is mainly vibes, lyrics are REALLY GOOD TOO but vibes for the neutral ending specifically…Its kinda nostalgic and childhood wondery (I LOVE SUFJAN STEVENS SO GODAMN MUCH OMG) and thats very much how I feel Toriels house/general demeanor is like :3

But i’m kinda stealing from the fan assumption/theory that Papyrus is often the only thing that convinces Sans that some things he does ARE worth doing even in a repeating world

“how do I live with your ghost” “everything i see/feel returns to you somehow” “I wanna save you from your sorrow”

ok but the saving from sorrow thing has 2 meanings, 1 twords Papyrus and the other to Tori, cause ALSO stealing from the fan theory/assumption that Sans hides a LOT from Papyrus and while I dont personallyyyyyy believe it cause I think the King Papyrus thing was a one time REALLY difficult choice- BUT ITS SAD AND IT WORKS FOR HERE.

THEN! it also works for Toriel cause he’s saving her from sorrow from telling her about what the human is really like

SLEEPYHEAD! This is from Toriels perspective now!!!

Again, pretty self explanatory if youve listened to the song, “theres dust upon the stairs” OMG! DUST!?!?! LIKELIKELIKE UNDERTALE???!?!?!?

Also “I have never been the type to go to church, but I pray for her(Him) each night” Toriel is shown to be religious in Deltarune so id assume shes the same in Undertale…

“Please dont forget that im your friend”

DON’T FORGET!?!?!?!?!?!?!?!?!?!?!?!!?

But anywho- in an amv of this id think that… Toriel has no fucking clue whats up, cause Sans hasn’t told her, but she still “prays for him each night”/is worried for him cause CLEARLY HES UNWELL

DEAR THEODISIA….IS MORE SANS AND TORIEL/ALSO ASGORE THAN THE ENDING ITSELFFFFFFF BUT JUST HEAR ME OUT

Burrs whole thing is about his daughter… and Hamiltons is his son….

Toriel and Asriel…and Sans and Papyrus….IT ACTUALLY WORKS SO WELL AND I SOB IMAGINING THE AMV POSSIBILITIES

Asriel: you will come of age with our new nation, we’ll bleed and fight for you, we’ll pass it on to you AAAAUUUUGHHH

Papyrus: pride is not the word im looking for, there is so much more inside me now, you outshine the morning sun AAAAAAAAAAAAAAAAAA

Asriel will blow them all away by being KING some day, and Papyrus will by just being the coolest motherfucker in Snowdin and also ROYAL GUARD

[its-t-v-time]

do sans and you have to be genuine about it

i would never be ingenuine about sans who do you take me for

sexuality headcanon: yknow i used to think sans was the one singular token cishet in undertale but now i'm enlightened i see that he's bisexual

gender headcanon: again if any monster has been cisgender it's sans. cisgender in the way you skip the character customization in a video game you understand

a ship i have with said character: soriel's cute! i used to really dislike it but tbh it's grown on me. it's one of those ships where above everything else you haaaaave to be funny. you have to be doing eggs husband shit. and tbh i don't think they were having ao3 m/f yaoi angst through the door i think they start dating post canon (or in deltarune) and it's silly before anything else

a brotp i have with said character: in the most literal sense, him and papyrus. i'm always thinking about that toby fox tweet that's like "i have to restrain myself from writing these skeletons bantering for too long because if left to my own devices they will just crack jokes for all eternity" because it really shows. like i don't think it's controversial to say snowdin is the FUNNIEST part of the game. and from a meta bullshit standpoint i think creator's favorite oc + fandom's favorite blorbo is a neat dynamic idk

a notp i have with said character: don't make me say the obvious. ehh besides that idk, sans isn't really a character i care about shipping with anyone but the days of ooc soriel and mid sansby are long over so at this point i think there's no harm in frolicking and playing ^_^

a random headcanon: no one can watch any scifi movie with him if they're gonna be a pedantic bitch because he will just "sharks are smooth both ways" them. and he knows his shit he's a nerd so he can just use that to his advantage. alphys knows his tricks and just ignores him. papyrus knows his tricks and yet they still get into arguments about fringe (2008)

general opinion over said character: SANS MY BEST FRIEND I LOVE HIM <3 yknow there was a time where i said i hated sans because he was just eeeeeverywhere in the fandom but i was lying because every time i actually revisited the game i would be losing my shit every time he appeared. this was partially from me gravely misunderstanding his character but no yeah the hype was kinda deserved. that's sans! from undertale! like he's just such a crazy insane asylum character and all the shit with deltarune is just making him even more bonkers. i love my friend sans from the underground

[theriverdraws]

I have so many thoughts and feelings about Asgore x Toriel. It's just so depressing.

Talking about undertale first, Toriel seems to have moved on from Asgore completely, and even more, completely despised him for years because of his actions, which is fair. And Asgore on the other end really just held on to hope to be with her again, because what he really wanted was to have his family back and for everything to return to normal. Because holding onto that hope is all he had. But that could never happen.

I really appreciate how close they were when they were happy together, and even with how messy everything got after the kids died, they eventually reconciled in the post-pacifist route. Asgore working in front of Toriel's school and they're just chilling, and also the alarm clock dialogue where they're happily reminiscing and playing together.

One could interpret they got together again? But I mean, not to put soriel in the conversation, but considering all the neutral routes where they end up living together, and hints in the alarm clock dialogue, and that one ut q&a that implies they also live together post-pacifist route (or at the very least close enough she makes sans and papyrus lunch everyday), and yknow, everything in deltarune - it's pretty clear Toriel has moved on completely. And post-pacifist Asgore too it seems. And I'm happy for him.

But deltarune boy oh boy.

This isn't decades after their falling out where I'm sure both of them are just tired of this by that point. Oh no, this is probably not even that many years after at ALL, maybe it even happened after Asriel went away for college. We're literally watching them crash and burn right now and it's so bad. PLUS WE DON'T EVEN KNOW HOW IT HAPPENED.

And obviously it's not good to be together just for the children - sounds like a nightmare to me but that's probably a bit of projection on my part - and Toriel shouldn't be with him if she doesn't want to. But Asgore's financial and living conditions is just so bad, and to put salt in the wound he hasn't even moved on from Toriel yet, while she definitely has. (Or trying to, as soon as her ex stops sending her flowers and flirting with her in front of another guy she was trying to flirt with. Sorry, that scene just kills me it's so good).

I really hope Asgore can get better from this state soon since I don't see them getting back together at all. I assume their falling out wasn't so simple as Toriel just not loving him anymore, there's definitely something bigger there and I would bet it's something involving him losing his job at the police department cof andDessmaybe cof.

But even then I still hope we manage to hit that reconciliation we have with undertale because they were so good together and can be very good friends again. We can only hope.

[drawing-every-utdr-character]

Heya! You said we could ask your opinions on things, so I’m here to ask a few questions!

(If any of these were previously asked, I’m sorry).

(You don’t need to justify your anwsers exept you want to).

1. What are your favorite character in Undertale? What about Deltarune?

2. What are your favorite moment of both games?

3. Do you belive in narrachara(the theory that Chara is the one narrating Undertale)?

4. Are you on the AU comunity? If yes, what are your favorite ones?

1. my favorite characters in undertale are mettaton and the nice cream guy. mettaton because i relate to him a lot, and the nice cream guy because i love how sweet and optimistic he is. my favorite characters in deltarune are rouxls kaard and tasque. rouxls because he's stupid as fuck (/pos) and tasque because funny kitty

2. for this one i could give a lot of answers for different reasons.

for undertale: i like every scene with sans and papyrus because they're basically narrative foils so they're always funny together. i like the scene where mettaton first shows up both because he's my favorite character and because i love how energetic it is. i like the encounter with snowdrake's mother because it's basically the most depressing thing in the entire damn game. i like the scene during mettaton's show where he takes phone calls from fans because it shows the complexity of his character.

for deltarune: i like the opening because of the way it introduces kris's name (my only complaint is that none of the text can be sped up so it always takes a long time...). i like the ferris wheel scene for obvious reasons. i like every scene with rouxls kaard because he's stupid, i hope he tries to be a villain again next chapter. also every scene with queen but i think everyone shares that opinion. i don't have as many answers to this one because it's been a few months since the last time i played deltarune, i'm playing it again literally as i write this tho

3. out of every undertale theory, this is the one i have the weakest opinions on, just because i'm not very invested in chara. i think it could be true but i'd need to read more about it first, which i'll do eventually

4. when i was a kid and i was first getting into undertale i drew a Little bit of au stuff because i wanted to be cool but i have since accepted that i'm not..... invested in undertale aus at all. i Would be if they explored the possibilities of aus of the entire game, but instead all of them just focus on sans. which sucks for me because the undertale tag both on here and on ao3 are just full of sans aus where they're barely even sans anymore. don't get me wrong, i love sans too, and i'm not trying to rag on people who do like undertale aus, but i want to read about the relationships between characters that are actually in the game, yknow?

[fellcharas]

yknow, how can we be absolutely sure that the creation of his that gaster fell into was the core?

of course, there isn’t always a need for repeating the name, and toby could mean that the core was what gaster fell into, but i reeeally don’t think that’s what happened. i’ve talked before about how it’s possible gaster fell into a black hole (a likely accident from the creation of the machine in sans and papyrus’ basement, assumed to be a time machine), but here’s some other evidence:

geothermal energy is the thermal energy in the earth’s crust. it originates from the formation of the planet, as well as radioactive decay of materials in (uncertain but possibly) equal conditions. it’s very, very hot in temperature.

this would make sense, given undertale takes place in the underground - gaster would likely have harnessed geothermal energy and, as alphys says, convert it into magical electricity. she cuts herself off out of embarrassment so we don’t know much beyond the structure of the core and how it works, but it can be assumed that if it’s converted into magical electricity, this must aid in the function of living for monsters somehow. however, gaster is said to have been a slow worker, which could be why there aren’t as many monsters in the underground as we’d think (an easy way to save time for designing unique characters on toby’s behalf), as many of them could have died out due to poor living conditions.

but... how would gaster have shattered across time and space by falling into the core, something that as far as we know, only converts geothermal energy into magical electricity?

he “vanished.” he “shattered across time and space.”

(x)

this was gaster’s next experiment. this was after he created the core. negative photon readings, meaning there’s no light, and the darkness keeps growing - sounds pretty damn similar to a black hole. a black hole of this caliber could no doubt destroy a machine. and a common thing with time travel is black holes, given that many perceive them as actual “holes” and “tears in reality” rather than celestial bodies. if one were to avoid the singularity (a region where space-time becomes infinite), they could theoretically end up in a different space and time.

so gaster fell into a black hole, created by his time machine. whether it was on accident or he intended to do so is unclear. i don’t know why he would do so willingly, but in entry number 17 he doesn’t seem very worried about it. and - given that there is such a thing as the black hole information paradox - it makes sense as to why everyone would forget about gaster. because his information is lost to the outside universe, the universe that remains outside of the black hole.

what does this mean for deltarune? well, it’s entirely possible gaster could have entered more than just a different space and time... perhaps a new universe. with different rules. as toby said. there’s the theory of black holes creating new universes, purely hypothetical, but given that this is fiction we’re talking about it could be possible that this is the case.

is gaster the god of deltarune’s world? what role does he really play, given all of this speculation? what’s his goal, why is he doing this, if he even is? i don’t know. let me hear your thoughts though, i’d love to hear them

[a-snow-decahedron]

You should not have asked for cursed ideas because i have a bunch of them to share and curse people with

But the craziest of all of them, I need to say, is that, one day, for no reason at all, i said "what if sans and jevil were twins?"

And oh boy, (this is a damm rollercoaster im already warning u), i didn't stop there

I imagined half of this before chapter 2, and then i updated it after. Im going to say only the uptaded version

So, Sans (also Sans' name is "Boone" u need to know) and Jevil are twins, but Papyrus is gaster nephew. Also, gaster is actually "Aster" and his brother (papyrus' dad) is Wingdings, both of them are scientists, but WD is more important. Papyrus also has a twin whose name is ACTUALLY Sans. Papyrus family is made of humans, papyrus is a human, and he is from a universe called "unrelated" where monster and humans had a battle, but it end up in peace. One day WD invents a machine to travel between universes but he ends up dying in the experiments. Aster cries bc his brother is dead but improves the machine and travels to undertale world. Sadly, his body gets deformed, so monsters from ut cant tell he isnt one of them (this is before asriel is born). He comes back to his universe finally feeling he can be smth more than his brother shadow. Dont ask me how bc i didnt think that much but he becames he royal scientist using the name of his brother (wingdings gaster) while also working in having a new body in his own univers (oh yeah he also plans to make undyne the "great warrior" and injects determination on her eyes bc he belivee she is the only one who can survive bc she is already determined, she does, but the injected dt is now dormant inside of her body)

Evently he opens a portal to deltarune too, and learns about dark worlds. He is kind of going insane now and he meets with the titans (for reasons) who reveal that his world is a videogame and his existence doesnt matter. He makes some deals and he has powers now bam

He enters in contact with seven manlets (three being jevil, spamton and sans who is called boone) to make a new body later and also destroy his own universe (the gasters followers would be the versions of that world of the monsters we already know that have been destroyed) and idk makes holes in his nephews hands (like jesus himself) bc he didnt want to be alone with the holes then he jumps in the core and papyrus and sans try to escape his new followers by going through the machine and end up in the deltarune world, but they fall into a dark fountain somewhere and die, but like, not totally

They end up being selfaware amalgams that can shape shift lololol they meet BooneSans and Jevil who are kind of not fine at this point, and both trust in gaster, so papyrus and his twin tell them that gaster is actually not that trustful and will not give them freedom and they believe for some reason

Papyrus and twinSans decide they need to separate or else gaster is gonna take their undead corpse (did i mention they are kind of immortal now?), so the four of them make a plan

TwinSans gives BooneSans their soul (they can survive without it now), so he can swap places with them and go to the light world, but the game would crash if they stayed with the same names so they swapped names too

Sans (the skeleton one) makes a copy of the machine and they go to the light world pretending to be brothers bc papyrus shapeshift to a skeleton... Or so they thought. Sans didn't build it correctly and they end up in undertale world trapped :))

But like, the universes had a half reset bc the codes were too confused, so sans and papyrus notice they startes forgetting about their twins and the same goes to Jevil and Boone, so papyrus draws the "don't forget" thing and boone sings that one music yknow

Sans tries to talk to alphys (bc she is the scientist who replaced gaster she has to be good) so she can help him... But she isnt in the best conditions bc she just created flowey and the amalgamates- anyways they both fail but now gaster has alphys in his aim bc she is a WONDERFUL PIECE in his words or smth

Oh yeah also jevil fights wit spamton, they divorce, jevil is so sad that he doesn't notice gaster took papyrus twin and they die :( jevil eventually forgets about them, goes totally crazy, and then is locked up

Now we are in the same point of time in the games and papyrus is incapable of sleeping bc hes dead bam bam

But why would gaster want seven manlets? Well, i said it before, he wants to make a new body. After jumping in the core, hes shattered, and he gives a piece of him to each one of the manlets to eat. Eventually they will melt with only one body part left, he will take all of the body parts, make a new body, "enter" inside of it and ascends to [[HEAVEN]] (he will became god). He is obsessed with this bc the titans told him about us (the player) and he wants to be like us, he is putting the player in all of this adventures so WE can have fun

He is manipulating kris bc they are also under their brother, asriel, shadow so they can understand each other somehow idk

When you do a genocide route sans actually doesn't die bc you hit a ketchuo inside of him and he takes papyrus who also can't die and both go and, with the energy the player has provided, make the machine work and go to deltarune find their twins that they almost forgot about

AND THEN DELTARUNE STARTS

Well, is an idea i like to make more and more nonsensical and illogical with time, bc it doesn't have any base on canon. I swear im not like this most of the times

Anyways, am i the ask from your dream?

[Image description: A two panel comic showing a Tumblr Anonymous talking from their car to a fast food employee. In the first panel, the Tumblr Anon is speaking, their speech bubble extending to he top of the screen, implying that the text from the ask is what the character is saying. In the second panel the fast food employee holds a couple of plastic cups and is staring at the anon in shock. End of ID.]

[swordsxsarcasm]

MORE deltarune spoilers because i just finished playing from ch1-2 on a complete save file

ok so first things first:

1. spamton: i thought about it, looked around some more, and yknow how the butler in the queen's mansion cafe (after the fight) talks about how he built that body for a lightner? im pretty sure the lightner in question is mettaton. or, the ghost that Becomes mettaton. with spamtons final form being "spamton neo", the resemblance to mettaton neo in the geno route of undertale, and mettaton still being a ghost in deltarune, im pretty sure that mettaton had wished for a body like that, and the darkner running the cafe answered that wish by making the machine found in the basement.

2. onion-san: after two years, i finally heard onion-san's secret. or, both secrets, actually lol. so apparently onion-san has been hearing part of a song coming from deep under the water, and thinks that they'd heard the entire song before, out deep in the ocean. explicitly says that it's not a new song. they then say theyre going to investigate more and to come back tomorrow (ch3) to hear what else they'd found out. i have two theories about this, one, being that the song that onion-san is hearing is from the humans, and two, that the song is from the darkners.

the human theory is something ive been thinking on since i started replaying deltarune. im pretty sure this world is a timeline where the humans lost the war mentioned in the intro to undertale, and were sealed underground instead of the monsters as a result. the bunker is possibly the entrance to the underground, and kris somehow got out. kris's dialogue about humans seems to imply something dark, with the book about humans on the top floor of the library (accessible in ch2) having "pictures of unfamiliar humans", to which kris immediately slams the book shut. snowy and monsterkid, in ch2, down at the bunker mention that kris knows something about the bunker, and that whatever is in there is scary. this could be another entrance to the dark world (now that we know kris can open them as the knight) but it could also be the underground, where all the humans have been sealed inside of. humans also seem to be relatively unknown and somewhat of mythological creatures, with movies being made about them, and one of the npcs in the apartments asking questions to kris about if their blood hurts/where skeletons come from if humans have them inside of them.

the darkner theory is less thought out on my part, but still possible. the further underwater you go, the darker it gets. its possible that there might be an entrance to the dark world underwater, or maybe the dark world is simply part of the real world, and just unknown/hidden away. this could also tie into the bunker possibly being an entrance to the dark world, and might be the "true" entrance, but its been locked and so the worlds are separated. in ch1, (if i remember correctly) seam and the king mention how the lightners locked them away, and that the dark world wasnt always like this. ralsei also mentions that the lightners and darkners used to live side by side, almost symbiotically, with the lightners giving the darkners purpose and the darkners helping the lightners fulfill their journeys/wishes. if kris knows about it, its possible this isnt kris's first adventure in the dark world, and probably was alone the first time. i can see how that would be terrifying for anyone, let alone a child. kris probably locked the bunker so that no one else would get stuck in there/none of the darkners would come out. it could also possibly be that the "true"/"real" kris wants to release the darkners, but us as the player sealed the bunker somehow, hence why kris keeps removing our control and opening new fountains. there isnt as much to go off of with this theory as the human theory, but i think theyre both possible.

3. ok enough lore talk i have to mention it. THE DUCK. in ch1 when you make the thrash machine you can make a duck, and it sucks, and susie and lancer blow it up. the end. BUT IN CH2, ROUXLS KAARD BRINGS THE THRASH MACHINE BACK AS A BOAT. and if you played through from ch1-2 and got to customize the machine/make it into a duck, theres different text!

AND. to make matters even better, when you fight giga-queen at the end of ch2, and the thrash machine is modified into a mecha for you to fight her in, you ALSO get a special ability if your thrash machine was a duck! i forgot to grab a screenshot, but its similar to the standard laser upgrade in the act menu, except it (supposedly) sucks. i did notice that the duck version, in addition to attacking, also heals you when you activate it? which is great. all in all, i suggest playing from ch1 so that you can get the duck thrash machine. 10/10

4. the saddest news, papyrus: even if you tell sans you'll hang out with his brother tomorrow in ch1, you still cant meet papyrus in ch2. sans says to come back when asriel comes back to town (which is a whole can of worms, because sans shouldnt know asriel yet since hes new in town. unless toriel blabbed about him while fucking befriending him) which will probably be chapter 6/7 :( i miss papyrus so much im very sad about this.

i think thats it, but then again theres so much that hasnt been explored yet. this is just my thoughts/stuff ive encountered in my playthrough. very hyped for ch3 sjkdgfksdhfhj

[bonepranks-a]

* verses

aight so since i put most interactions into their own verses, i have like a million, and oftentimes certain interactions will sorta create new ones. so i’m going to attempt to list all the verses i have. i will specify if they’re with specific people. (i may use the word timeline instead, they are generally the same thing, but sans will always refer to it as a timeline whereas i will usually call it a verse.) also, as you know, i don’t tag my verses -- but it’s helpful to know.

this is well over 1500 words so i’m gonna just stick it under a cut. i listed the people who have specific verses in the tags so u can read it if you want??? i mean everyone is encouraged to read it but yKNOW. up to you guys <3

GENERIC VERSES

pre-undertale sans and papyrus grow up in hotland with gaster. sans works as his lab assistant/apprentice. gaster falls into the core, “dies”, the boys leave hotland and move to snowdin.

neutral/post-neutral in the flawed pacifist ending (aka the one that allows you to load from your last save and do the pacifist stuff), sans continues living in snowdin, life continues as normal until a reset happens. for all other neutral variants, see this post.

genocide for obvious reasons, stuff in this verse will only take place during the events of a genocide run, as sans dies. however, in a verse where this is not the first genocide run, certain events may change, including but not limited to an aborted genocide where frisk doesn’t come back after sans kills them, and life continues. this will look a lot like any other neutral run where papyrus is dead, but he’s more fucked up probably.

pacifist/post-pacifist the pacifist route goes as it does in canon. afterward, sans goes to the surface with everyone else. however, he makes frequent trips back underground, both to help other people move, and to visit those who decided to stay behind. 

abandoned pacifist/deltarune in a pacifist ending that occurs after many different routes and countless resets (many of which sans remembers), sans accepts the futility of seeking a real ending of any sort of happiness. he manages to find a way to leave his timeline. he does not believe that this is the end, and is afraid of what will happen if frisk resets again. he has never tried it before, and his method is purely theoretical, but he manages to take papyrus and escape the timeline before anything bad can happen. he leaves a seemingly peaceful and happy life on the surface, and ends up in the deltarune world. papyrus’ memories of their past life have somehow been erased (perhaps for the best), and sans is torn between relief that they seem to be safe now, and guilt for leaving everyone else behind without a word. he actually fakes his and papyrus’ deaths simply so that no one worries about them or tries to come looking. he’s not particularly happy, but he can’t find a way to go back either. he buys the grocery store and tries to find answers about why he ended up in this specific world that is so unlike the one he knows, and yet eerily familiar at the same time.

CHARACTER-SPECIFIC VERSES

vertebralheights 001 bo and sans meet as children when her father and gaster worked together. they hit it off, but after all the other skeletons leave hotland, she and sans lose contact. it’s only many years later that they reconnect quite by accident, and they don’t even recognize/remember each other until they find old notes and photos that jog their memories. they meet pre-undertale, and their relationship continues long into a positive neutral ending. as sans learns more about resets and their circumstances, he begins to do research, and bo helps him out. if this is a situation where alphys has disappeared, they move back to hotland and continue work there. eventually, pacifist happens or whatever, maybe they go to the surface, we haven’t really gotten that far.

vertebralheights 002 the origin is the same as in 001. however, it diverges into any ending where papyrus is dead. sans runs away to vertebral heights and stays with bo -- they come to the same conclusions about how they used to know each other. sans is determined to find a way to stop the resets - but only once papyrus is back alive. if this is also an ending where alphys is gone, they eventually go to the lab in this verse too.

vertebralheights 003 after bo’s parents die, she contacts sans and comes back to hotland. she stays with the bros and gaster up until gaster’s “death”, and when they do eventually part ways, they slowly lose touch but don’t forget about each other. they probably reconnect again post-pacifist when sans stumbles across VH.

cynicalborne 001 ( paired with mercy-heart 001 ) post-pacifist, sans and papyrus choose not to stay in the town the monsters have set up (though he and papyrus pay frequent visits), and move to nyc. sans buys a closed down bodega and runs it, living in the apartment above. sans also somewhat accidentally befriends a human named os. they somehow hit it off, and when he loses his job and apartment, papyrus invites him to stay with him and sans. as time goes on, sans and os completely fall in love. other than cryptic warnings from gaster that they should not be together and that sans needs to focus on finding a way to prevent further fresets, life is pretty good.

cynicalborne 002 sans and os still know each other - they’re even friends, but their lives are very separate. os is still working more or less as an arson for hire, and he attacks the monster town that’s popped up. sans finds out, and shit goes down. 

mercy-heart 001 post-pacifist, sans visits frisk frequently, though he does not live in the monster town on the surface. one day, chara manages to take control of frisk’s body and gives sans a cryptic warning about how this happiness won’t last. he laters finds out through them and through dream messages from gaster that the only way to prevent further resets is to take away the vessel the player is using -- aka destroy frisk beyond saving. make it so that they cannot reset or reload at all, by literally erasing them from existence. sans refuses to do this however, and tries to find a way to simply disconnect the player from frisk’s soul, or removing only the ability to save and reset.

mercy-heart 002 more or less the same, it’s post-pacifist, except sans does stay in the monster town and probably ends up getting together with toriel because his love for her knows no bounds. life is good, there’s no players interfering, they can just be a happy family, and sans can just help frisk cope with their own depression without worrying about everything else.

we-believe-in-you-crew 001 sans meets bonny when she arrives in snowdin -- due to his promise to toriel he decides not to hurt her. instead, he helps her as best he can, encouraging her to stay in snowdin with him and papyrus and not to venture too far away for fear she might be killed. they eventually catch feelings for each other, and while they both know it, they never do much about it. everything is very subtle with them - mainly because sans knows they’re living on borrowed time. when she eventually makes it to new home, sans mercy kills her in the judgement hall because he can’t stand the thought of her being killed by asgore. 

primaautomaworld / qvietstcrm 001 (these are just getting lumped together because they happen in the same verse.) sans and mettaton used to be childhood friends, back when alphys worked under gaster and mettaton visited frequently as a lil ghostie. he would often play with sans and papyrus, and he and sans even had lil crushes on each other, not that anything ever came of it. however, once mettaton became corporeal and moved on to becoming a star (and after gaster’s disappearance as well), they completely lost touch. it’s only much later that sans calls up mettaton and invites him to stop by snowdin. the reunion between all three of them is really really good, and mtt and sans start up the flirting hardcore until they finally do just get together. MEANWHILE IN PAPYRUS LAND, he starts going out with a siren from waterfall named storm. sans meets them one day during work, invites them back for dinner, storm and papyrus hit it off really well, and the rest is history. it’s really cute uwu  

fluersamour 001 sans and chara.... knew each other before she died. they would play together along with papyrus and asriel when gaster had meetings with asgore and brought the kiddos. they weren’t necessarily close friends, but they were pleasant. good companions. over the course of genocide routes, they’re constantly fighting and she’s killed sans multiple times. it’s a thing. but eventually, it stops. they reach a stalemate. they don’t want to kill each other anymore. and eventually, they start talking again. about the past. about her time in the void, and meeting gaster. it’s not exactly normal friendship but it’s.... something.