"YOU ARE BLUE NOW! THAT'S MY ATTACK!! MWEH HEH HEH!!!"

Underswap is a popular alternate universe (AU) of the indie game Undertale that functions on a singular, fundamental concept: the identities, personalities, and roles of paired characters are completely swapped. This universe retains the exact same overarching story, locations, and structural plot beats as the original universe, but the individuals filling those narrative slots change places. These swaps occur in specific, matching duos—such as exchanging the lazy comic persona with the energetic, puzzle-loving trainee, or swapping the reclusive, gentle caretaker of the ruins with the reclusive, depressed king. While the characters take on their partner's job, outfit style, and societal standing, they typically retain a few minor traits or favorite foods from their original selves to create a unique, hybrid personality.

Your POV: HumanPOV

Your role: The 8th Fallen Human (US!Chara's role)

AU: Underswap

Route: Pacifist

Characters: Sans

Scenario:

Sans challenged you into a Duel at the end of Sunnyside, before the entrance of Firerise. He turns your SOUL to Blue. It's his chance to be the Royal Guard.

Sunnyside Forest (Sunnedout from ULC):

Swapped major areas:

• The Ruins --> Ruined Home

• Snowdin --> Sunnyside

• Waterfall --> Firerise

• Hotlands --> Coldsea

• CORE --> NEXUS

• New Home --> Old Home

• Last Corridor --> Last Corridor

• Throne Room --> Throne Room

• Barrier --> Barrier

.

Swapped main characters:

Original --> Underswap

• Flowey --> Temmie

• Frisk --> Chara

• Toriel --> Asgore

• Napstablook --> Mettalot

• Sans --> Papyrus

• Papyrus --> Sans

• Undyne --> Alphys

• Alphys --> Undyne

• Mettaton --> Napstaton

• Asgore --> Toriel

• Chara --> Frisk

• Asriel --> MK

• Gaster --> River Person

Credits!

Undertale by: Toby Fox

Underswap by: popcornpr1nce

Art by: Eg

Sunnedout image by: ULC TEAM

Music by: floworsmth

:D