So, Frisk and Chara trade places. This is probably the only thing that out right changes without a reason.
Frisk and Asriel come to the same plan as in Undertale. Frisk poisons themselves and dies, Asriel takes the soul, and the plan fails.
They both die and their remains are buried in the start of the ruins.
Asgore, instead of declaring war on humanity, takes Toriel's advice of getting 1 human soul and going to the surface.
They wait for the next human, who turns out to be unused human sprite. Seeing that they're only a child, Toriel and Asgore take care of them until they die of an unexpected illness they had before falling.
They requested to be buried in waterfall and their spirit can still be accessed there through the mysterious door.
Asgore, sad and disheartened from losing yet another child, absorbs the soul and heads to the surface to gather the rest of the souls.
The humans prove too powerful for the depressed and kind Asgore and he makes his way back to the underground.
Others, knowing he'd go do this, were awaiting his arrival with the souls but seeing him nearly dead, they rushed to save him.
Alphys ends up having to transfer what remains of him into a flower. Unfortunately, Asgore loses all his memories as a result.
Toriel, having lost her whole family in the span of only a few months, steps down from the throne and takes Asgore or now, Flowey, with her to the ruins where she can grieve in solitude.
She and Asgore find, through sheer determination, Frisk's corpse has reanimated itself but through the trauma, has become an angry and vengeful creature. Toriel and Asgore are tasked to keeping Frisk at bay in the ruins to protect the rest of the underground.
Before Toriel left, she held an election for the new ruler of the underground as she felt the people should decide. Muffet wins by having all her spider family vote for her. This outweighs the amount of monsters in the underground by thousands.
Undyne continues to serve in the royal guard but without the search for humans as mo war was declared. Shes there to protect the citizens. Unfortunately, due to an accident where she protects MK, she becomes brain damaged and can no longer serve. Though, she runs a training gym/shop in waterfall now.
MK saw the their idle fall protecting them. They begin to train in order to 'avenge' Undyne. They unlock their fire magic along the way and soon become the youngest to serve in the royal guard.
Alphys still makes Mettaton but the amalgamate experiments never happened, as again, the underground wasn't desperate to leave yet.
She continued to hang out with Bratty and Catty. They introduce her to Fuku who introduces her to Grillby. Alphys then finds an anime called Elemental idols and they watch it together.
Loving the anime so much, they both ditch their jobs to become idols. This dose upset Mettaton a bit but he soon finds comfort in cooking and since Alphys helped him so much, he shares the entertainment industry with them and mostly focuses on cooking media now.
Mad dummy sees Mettaton going for his dreams and thinks "Whoa, I wanna do that too!" So they find the Mew Mew body and try out cooking. It brings her so much joy that she fuses with her new body and decides to take over Grillby's in Snowdin.
Sans and Papyrus, free of trauma and science based backgrounds in this AU, live relatively chill lives in Snowdin. Sans learns that to see the surface, you need a human soul and he trains to get one. Though, he's not very talkative. So he appoints his lacking in confidence ghost friends Napstablook as his translator. Napstablook, not wanting to let a friend down, dose their best and slowly grows confidence from being Sans' voice.
Papyrus, though still has trouble making friends, is doing his best and since he's not focused on the guard, he wants to go into puzzle making. So he'll appear by random puzzles to make and test them.
Chara falls into the underground and is like "wtf is this." And goes on an adventure.
Gaster stands ominously in the files, waiting to be noticed one day.
