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Impacted Reality is an AU made by Droidy365, following River Person and Flowey instead of Sans and Papyrus, and Gaster plays a big part in the story too.

Wiki Sneak Peek

Lots of information lies behind spoilers, so some story points or new characters will be absent from this page (for now).


Undertale Characters

Sans and Papyrus

Sans and Papyrus are completely absent from the story, aside from a few references and backstory stuff. Despite this, they play a very big role, as this AU would not exist if it weren't for them.


Flowey has mainly Papyrus' personality, but with a love for death traps and making muffins instead of spaghetti. He also likes to eat a bit too much Monster Candy. He's a major character in both the Ruins and Snowdin story arc. He 'upgraded' the Ruins puzzles, much to Toriel's disgust. Wears a piece of Papyrus signature scarf.


Toriel is unfortunately stuck in her house because all of the puzzles Flowey added to the Ruins are one-way only. She's more quickly frustrated and angered due to this.


Napstablook is the same, but challenges you in Deep Dungeons during the Genocide route, to avenge his fallen cousins. He uses a mix of his ow attacks and Mad Dummy's and Mettaton's weapons.

River Person

Passive RP

River person replaces Sans, but he's quite different from him. Instead of making puns, he makes riddles, and he's a very confusing character that's full of mystery. He plays a very important role in this AU, even more than Sans in the original Undertale. Has a skull similar to Papyrus' visible behind the hood.

Fuku Fire (Green Fire Girl)

Fuku Fire Girl IR

GIF made by BattleblockB0ss

For spoiler reasons, she now manages Grillby's, as he isn't in his usual role either. The restaurant still is named Grillby's though, as a memory to him.

Snowman battle


When you attack the Snowman with his own Snow Piece in Genocide, he gets mad and attacks you, triggering a battle. His nose is still colored orange during battle, technically making him the only character with a battle sprite that's in full color (as the rest was white already).

River Person still talks about the snowman during the neutral endings.


Undyne IR

Undyne doesn't change too much, but she's now friends and with Underfalls' main character, Sketch Bones, and she often has friendly fights with him. Her armour is a mix between her regular UT armour and the Undying armour, with a few other small changes. Her Undying form is completely redesigned.


Gaster got out of the void, and now reclaimed his position as Royal Scientist. He's very serious and bossy, and constantly calls Alphys lizard. Eventually she told him to stop, which he respected, but it still accidentally slips out most of the time. He used the DT Extractor the destroy the Amalgamates. He's also the host of the educational Gaster TV. He converted MTT Resort into a casino to fund the CORE.


Alphys is now Gaster's assistant, and really hates it. She helps Mettaton escape from Gaster's control, and does anything she can to do so (including going against him to help you in subtle ways).


Mettaton is now remodelled by Gaster as a full on Human Eradication machine. His box form was scrapped, and his NEO form was improved. His body has a grey colour scheme instead of pink, and his face looks more serious and masculine. He assists Gaster at his shows. He has 4 different fights depending on your actions:

Mettaton WD: The Neutral fight. Here he is under Gaster's control, and fights you to bring your soul to Gaster.

Mettaton EX 2.0: The Pacifist fight. In this fight, he escaped Gaster's control, and took over Hotland. This is the most similar to Undertale's fight. It also includes a quiz revealing some of Gaster's secrets.

Mettaton EX 2.5/Betrayed Star: This fight starts when you attack Mettaton EX. He is much more aggressive, and has stronger attacks.

Mettaton NEO 2.0: The Genocide fight. Actually a battle this time. Here, he has accepted his Human Eradication programming to destroy you.

Royal Guards 01 and 02

These 2 now work as Gaster casino's bouncers.


Muffet now works in Gaster's casino as a baker, since her old home got replaced by a second lab. The job pays well, and the Ruins spiders got united with her spiders, closing the shop there. She guards the keys to the CORE.


Not much can be revealed about them without spoilers.

The other characters barely change, if they do change at all.

Deltarune Characters


Berdly is one of the Home inhabitants.

Noelle and Rudolph Holiday

Noelle and her dad are inhabitants of the Snowdin Depths.

K Round

While, not physially appearing, K Round can be seen on some casino posters.


Susie is an optional miniboss in Deep Dungeons. She got locked up there after nearly destroying Gaster Resort when Undyne denied her request to join the Royal Guard.

There is one more character, but it's a spoiler right now, and canst be revealeth yet. All that can be said is they are very, very interesting...

Added Characters

Monster Candy Bowl monster


A hidden boss in the Ruins. Attacks you when you take the second and last candy. Only has green attacks, so he can't kill you. Cannot be killed outside of Genocide, since he requires 2 hits to die in the other routes, but escapes before you can deliver the second one.

Birdon Wingbury

Birdon Wingbury is an eccentric bird living in Home who collects shiny objects, even going so far as stealing them. However, he always stays polite, and usually tries not to hurt anyone, and never kills. After True Pacifist, he somehow obtains the Legendary Artifact, a treasure he has searched for for his entire life.


A Canine Unit member patrolling the icy Snowdin Depths.

Grandpa Semi

Grandpa Semi resides in the house visible in the Snowdin Depths.

Sketch Bones


Sketch Bones is a skeleton pirate living in Underfalls, and possibly related Sans and Papyrus (though this is undecided as of now). Despite his slightly evil appearance, he is a pretty nice guy, only fighting you during Genocide. Quote: A friend of my friends is also my friend! But not their friends. Else everyone in the world would be my friend, and you just don't want to be friends with some people out there...


Sketchy is Sketch Bones' parrot, and just like his owner also a skeleton. Usually he's used by Sketch to deliver messages.

W.D Drone

Drone - Copy

W.D Drone is, like the name says, a drone, made by Gaster to keep people out of the lava in a new area of Hotland. Made to resemble MTT's upper body. Has a female gender programmed into her.

Photo Guy

Photo Guy manages a photo booth in the new area, with pictures of some important characters.


Hotdogpants is a joke character that never appears physically, but often gets mentioned by NPC's throughout Hotland, including W.D Drone, who says "Poor Hotdogpants" when she explains why she can't drop you onto a moving platform, implying death by lava. There are also a few Missing Posters scattered around. He was originally the person managing the casino.


A shady shopkeeper in a corner of Gaster's casino. Usually a black puddle, but shape-shifts itself into a pitch-black version of the person that's standing near him. Tries all kinds of shady methods to sell stuff. Also a common enemy in Deep Dungeons.

Droidy/General Kenobi

Droidy/General Kenobi is the self insert of the AU creator.



A meme-ish character related to Droidy in some way.


A new Royal Guard member mid-boss appearing in the CORE. She often acts like she's the captain, as in her words: "Undyne won't come here to do it". She also gets angered very quickly. Her backstory is a spoiler for now.


98-Bot Wiki

A bunch of robots patrolling CORE basement level 1. These will be featured in a stealth section, and one with broken weapon systems takes over the casino management until Hotdogpants returns, which probably won't ever happen. This is based on a scrapped character from Undertale.

Sansbot and Papyrusbot

2 robots made by Gaster to resemble Sans and Papyrus. Sansbot drinks oil, and Papyrusbot cooks electric wires.

Shadowy Shopkeeper

A shopkeeper in Deep Dungeons. Not much is told about him, aside from the fact he's one of the only imprisoned monsters who redeemed himself, and he likes the shadows.

The rest of the new characters are either very minor, unfinished, or locked behind spoilers, and cannot be revealed yet...


Undertale Locations



The Ruins got a major change-up, with Flowey replacing old and adding new puzzles everywhere, all 1-wayed. The perspective puzzles have collapsed, and a few new rooms can be found, including 2 puzzle rooms, a room with an Echo Flower Flowey practices speeches on, a small shop ran by a Froggit called the Hop Shop (not inspired by True Geno) to replace the abandoned bake sale, and a hole in a wall near Toriel's house, where she threw extremely over-baked pies at it to escape (despite being able to break through most things with her fire magic), where the Rock Candy can be found, which is literally just a rock from the wall.


Snowdin is mostly the same aside from Sans and Papyrus being replaced, though the Rope Bridge Challenge collapses, dropping Frisk into the icy Snowdin Depths.


The only change here is a hole leading to a new area called the Underfalls, and a little Temmie Village expansion.


Snazzy Bot

Hotland changed massively. Gaster's shows are different from MTT's, and Undertale the Musical and Muffet's home are replaced by a weapon testing facility/second lab. There's a new floor below the first one containing moving platforms and lava, as well as the photo stand. MTT Resort is turned into a casino built to fund the CORE, but Burgerpants, the hotel and the restaurant are just moved a floor up. Muffet also resides here now. This area also contains lots of Deltarune references.


The CORE has a basement, containing many robotic enemies.

98-Bot G Down

True Lab

The Amalgamates are replaced by Gaster Followers/Goners. There is also a room containing Gaster's other Mettaton designs, including the box form, one resembling UF! Mettaton, and one resembling Rouxls Kaard, as well as the original 98-bot design.

New Home

New Home now holds the entrance to a sinister new area...

Added Locations



As the perspecive puzzles have collapsed, you have to follow a newly opened path leading to the city behind the Ruins, a purple colored area with canals going trough them. This city is also the place where a lot of bird monsters can be found.

Snowdin Depths

The forest deep below Snowdin, a chilling cold area with the only warm-ish places being a few houses and a small restaurant located in an ice cave.


Sub - Copy

A cave system that's mostly flooded, located behind Waterfall and nearby Hotland. The monsters here are mainly aquatic creatures that can't live on land like most of the Waterfall monsters, as well as those who preferb living around warmer water or sand. You can't even escape the Annoying Dog here, since he managed to get his little paws onto a yellow submarine...

Deep Dungeons

An area located deep below New Home, unwillingly entered the same way as you enter the Ruins. It is a maze divided into multiple layers. The top layers contain the houses of shadow dwelling monsters, while the bottom layers are a prison for monsterkind's most sinister and malicious creatures...


  • There are certain types of food that have a chance of giving food poisoning. These items are shown with the colour Magenta.
  • Underfalls has an oxygen mechanic.
  • All Hard Mode exclusive enemies appear in Deep Dungeons.
  • The Alphys date and True Lab sections are moved to occur before you travel through the CORE, and 2 additional requirements are needed for the True Pacifist ending.
  • A few new weapons are added, these being the W.D brand Magicsaber, which basically is a lightsaber with magic, and a taser Alphys is selling to fund her own private projects.
  • There are more endings, including ones for Muffet, Volcana and a few more OC's that are locked behind spoilers. Some endings also change.
  • The Genocide area themes are darker versions of the regular ones, instead of the usual slowed down ones.
  • The Face Steak is now called Hand Steak, and is shaped like Gaster's hands.





  • The next trivia is true.
  • The previous trivia is false.
  • The first 2 trivia's are a paradox, just like the IR timeline.
  • Impacted Reality is an Impacted Timeline, a concept made by Droidy, which is a timeline that's created by something that should be impossible, like a glitch or paradox.
  • This AU was inspired by FlamesAtGames' Floweytrousle (which is a part of the OST) and Ethan Harper's River Reaper (Version 2 is here).
  • A bunch of the AU's tracks contain Deltarune leitmotifs. Another Him is one of Gaster's motifs (instead of Undertale's Gaster's theme), the Casino theme is an Electro Swing Rude Buster, Deep Dungeons contains a bit of Field of Hopes and Dreams and Susie's battle theme is a remix of Vs Susie.
  • The events of Undertale Yellow are considered canon to this AU.
  • Mettaton is basically a less extreme and edgy Underfell Mettaton.
  • Many scrapped things from UT make an appearance, these being the 98-bots, the scrapped food items, Royal Guards 03 and 04 (possibly), the unused MTT EX heads, and even one of the test NPC's, locked up in Deep Dungeons for ruining Gaster's view by being poorly drawn.
  • In the creator's head-canon, Gaster has a similar voice to Emperor Palpatine from Star Wars.
  • Star Wars is referenced multiple times throughout Hotlands, and the platform section is inspired by the planet Mustafar.