Long ago, two races ruled over earth: humans and monsters

One day tragedy struck, a blizzard worse than any before it struck the human village and the humans believed the monsters to be the cause.

The humans fought the monsters, and sealed them into a cave, using magic to curse them with eternal cold

Many monsters suffered, and more died.

PRESENT DAY:

Legend has it that a furnace powered by seven human souls could stop the winter and break the ice barrier that seals them underground

(Thingy of chara(?) falling into the underground blah blah blah game starts)

Ok time to start the actual story

haha lol jk I need to explain all the changes

Ok so the most major change is that undyne died due to the sudden change in temperature:

Alphys found her goop stuff and scooped it up and saved it, and since has been secretly using the royal scientist funds not for technological development but in an attempt to revive undyne

Meanwhile papyrus is walking around in waterfall, looking for undyne in a hope that somehow, he could find her (he doesn’t know that she’s dead, sans told him she’s just missing) alphys sees him, and sees an opportunity, she persuades him to come to the lab, then she knocks him out cold (see what I did there)

Papyrus wakes up a few hours later tied to a table and has a couple of wires and containers hooked up to him, most notably one labeled “remains” and one labeled “DT”

Due to the fact that he’s tied down papyrus is stuck there

A few minutes later Alphys walks into the room and tells him that he will be ok, and tells him that if the procedure works, papyrus can be part of the royal guard, when papyrus asks what the procedure is, Alphys doesn’t answer.

Slowly, papyrus goes back to sleep, and the vials are all injected into him

Once he wakes up again, he is now in a bed in a room that is similar to undynes, and is wearing a suit of armor also similar to undynes clothing.

Alphys walks in and tells papyrus that she cannot tell him where he is, and that he will stay here for the next few months.

Over the next few months papyrus is nurtured by Alphys, but notices something, Alphys is getting increasingly more stressed, and is now preforming daily checkups on him, and soon papyrus starts to notice something else.

Flesh

papyrus is growing flesh on his bones

Flesh with scales

And something else, papyrus feels much more determined and stronger in general, along with the sudden ability to be able to summon and throw spears as well as bones now.

However, the flesh doesn’t completely cover him only parts of his limbs and face, he also looses vision in his left eye and needs an eyepatch, soon the changes stop.

Alphys realizes that her attempt at bringing undyne has failed and soon leaves the lab, and is never seen again.

Alphys has created papyryne

Papyryne never found the key to leave the true lab, and has turned to be the caretaker of the other amalgamates, papyryne has a lot of physical traits of undyne, while keeping most of the personality of papyrus, meaning papyryne is now actually able to do the good deeds he once wanted to do. Papyryne makes the true lab look nicer, and treats the amalgamates like family

TLDR: edgy papyrus and undone fusion go brrrrrrr

Aannnyyywwwaayyy during all those shenanigans sans has become very very lonely and quite depressed, as you can see in his battle sprite. He looks for papyrus everyday and can’t find him. He spends most of his time in his house or the judgement hall, or at least, he did.

Sans does end up meeting toriel, and in fact is at the door when you fight her. However sans never made his promise to not kill a human to toriel, as he feels that if there is an opportunity to melt the ice, he should take it. After you leave the ruins, sans will have run away and back to his house. As you go though Snowdin, all of papyrus’ puzzles are completely frozen over and easily passable, and there are no monster encounters. As you walk you leave deep footprints in the snow, and the player sprite is partially submerged in snow due to how much there is. When you reach snowdin, no one is there either, they all either left or died, sans an papyrus, being skeletons, are the only ones who were able to survive the cold. The river is completely frozen solid, and the ice cube machine is backed up with ice. When you reach the area where you would normally fight papyrus, sans will sneak up on you and start a battle. The battle is different depending on weather you killed toriel or not. If you haven’t, sans is simply fighting you out of obligation, and the fight is very easy. After a few turns of acting and sparing, sans starts to cry a little. He doesn’t want to kill anyone, stating the underground has lost enough, and spares you. If you attack, the screen turns black and then you go back to the overworld. no sans in sight. If you do not attack, sans will not say anything, and go back to his house. If you did kill toriel, the fight is a bit harder, but after a few turns, sans will run away.