Underswap was originally yeeted onto the world wide web by @popcornpr1nce, who has since abandoned the AU to the Undertale fan community after misinterpretation of his characterizations. It’s really a shame that we didn’t learn to be respectful and share like we did with Fellswap Red and Gold, hmm? HMMMM?
The story starts out near identical to the original. The monsters waged a war against humans and were sealed underground.
The War Hammer, Gerson, retired to Waterfall to study the ancient art of puzzlemaking. His good friend, the Elder Shopkeeper, also moved there, and the two meet up to reminisce about the olden days often.
The First Human, Frisk, fell into the Underground and was adopted into the Royal Family. The Prince and the First Human grew close, and after some time, they hatched a plan to merge their souls and cross The Barrier to bring back seven human souls in order to free Monsterkind. However, they failed, and the two royal children perished just as they returned to the Underground. [Some people swap out Asriel and Monster Kid, but I like the version where the Prince is left unswapped and MK is switched with Goner Kid instead. However, in the former, I headcanon that Toriel was pregnant when Asgore left, although neither knew at the time, and Asriel was raised without much knowledge of his father or his siblings by the good folk of Snowdin, since Toriel sent him away after killing her first human thinking that she couldn’t be a good mother.]
The remains were found by their parents, and the Prince’s dust was scattered over his favourite plushie who had kept him company as a child before the First Human fell.
In her grief for her fallen children, Queen Toriel declared war upon humanity to her people.
In his horror at his beloved’s decree, King Asgore renounced his title and fled with the First Human’s body to the Ruins of Monsterkind’s first home in the Underground, to be burried underneath the golden flowers on which they had first been found. He then took up the role of the Caretaker, wandering the Ruins in wait of more humans to fall so that he might keep them safe, trying and failing to perfect the pies his wife would once bake for a happy family.
A young lizard monster was one of the few responsible for pulling the Queen out of her mourning. Alphys approached the Boss Monster daily with a challenge, and eventually the Queen trained her up into the position of Captain of the Royal Guard, a protective group of bunnies that enforced the law.
Years later, an accident occured in Hotland, and the Royal Scientist and a few individuals became lost to this realm, and a single survivor, scarred and mad, fled the region to become a cryptid ferryman two skeletons appeared in Snowdin. The elder was a bright young monster named Sans, who loves astronomy, tacos, puns, and good-natured pranks. He is good friends with the strange fire elemental, Grillby, who runs a restaurant in Hotland. Sans became a sentry after proving his abilities to Captain Alphys, despite his poor AT and DF stats. The younger was a tall beanpole of a curious teen that eventually grew into that orange hoodie of his. He became a lazy social butterfly, and holds a sentry position near in Snowdin Forest. He’s a favourite of the dogs that run the local shop and inn, and a regular at Muffet’s, a bar that doubles as a bakery with fairly expensive pastries run by a spider monster named Muffet.
[Now, a main source of discourse in this au was over the skelebrothers, like their age order or signature foods or likes and dislikes. Please remember that these are only my headcanons, and you are in no way obliged to agree with them. Personally, I think Sans’ HP is fairly high even is his other stats are low, and he can use “shortcuts” just like his original counterpart. Papyrus has low HP but average AT and DF, and can walk on invisible tiles and clip through walls like his original counterpart. In playing the Judge role, he also has his karmatic poisoning ability].
A fish monster by the name of Undyne was the one to fill the role of Royal Scientist after many years of the position being empty. The Queen was impressed with her work on building an artificial soul, a robot named Napstaton who would go on to become the Entertainer of the Underground.
On a quiet farm in Waterfall, a pink ghost named Hapstablook cared for his snails to the sound of his cousin’s music.
