W. D. Gaster

W. D. Gaster is a hidden character in the world of Undertale. If the game is played normally, his existence is only hinted at, by characters such as the River Person. Otherwise, Gaster is hidden throughout the game's internal data and direct references to Gaster can only be found by editing the game's files and messing around with the game's Fun Values.

Although you are not able to fight Gaster, his stats were gathered by data-mining. His enemy type also happens to be 666, yet the enemy type before that is 100 (Asriel).

Piecing the clues together reveals that Dr. Gaster was the previous royal scientist before Alphys, and that he was responsible for creating the Core. However, he fell into the creation (which is implied to be the Core but may also be the strange machine located in Sans's Workshop) and his life was cut short. It is implied he was erased from existence, but that his consciousness is still present – forced to comprehend the fact that the world is the same without him.

Similar to Papyrus, W. D. Gaster speaks in all capitals and in a typeface different from most other characters.

Description
W. D. Gaster does not have an official known form, but there are two potential possibilities, both of forms have been encountered in Room that were planned to be in Waterfall.

Room 268 and 269
Editing the game's files so that the "Fun" value is capitalized and set to 66 will cause Room 268 (room_water_fakehallway), a mysterious hallway with a grey door, to appear between Room 94 (room_water_savepoint1) where the crystalized cheese is located and Room 95 (room_water11) where Sans' telescope is located.

The grey door leads to Room 269 (room_mysteryman) where a mysterious person (spr_mysteryman), who is widely believed to be Gaster, will appear. Unlike every other NPC, the person has no collision physics (As in, they can be passed through), and interacting with them will cause them to react in surprise and cause them to vanish while a sound effect plays.

Once the player leaves Room 269 back into Room 268, the door disappears from the corridor. The corridor itself becomes inaccessible once the player leaves it.

Room 123
Room 123 (room_water_prebird) is a removed corridor with tall grass that is presumed to connect Room 99 (room_water_bird) where the bird that carries you over a disproportionately small gap is located and Room 116 (room_water_friendlyhub) where the six-way fork in Waterfall is. The characters in this area mention that this corridor is a bug catching spot, it's unknown if is the bug-hunting spot that Toriel talks about in the beginning of the game.

An unknown character in the left side of the tall grass mentions that there is somebody with a creepy smile behind you, the unseen character presumably disappears after the dialogue is triggered. This encounter may be a reference to the Mystery Man seen in Room 269 who has what one would consider a "creepy smile" then disappears afterwards, but it is uncertain if this is just a different monster instead.

Room 272
Room 272 (room_water_redacted) is a dark room where Premonition plays and a figure in the room becomes more visible when walking closer towards it. Interacting with the figure will only bring up the message "< * [REDACTED]" in Wingdings which implies that a conversation was planned here but scrapped.

Attempting to check this room without altering something will just show you the Annoying Dog.

Exiting this room will lead a Sound Test room, which can also be accessed by having the game's fun value capitalized and set to 65. The Sound Test does not actually contain music found in the Undertale Soundtrack but instead has four tracks titled: "Happy Town", "Meat Factory", "Trouble Dingle", and "Gaster's Theme". The latter, however, is playable.

Main Story
W. D. Gaster does not show up in the game through normal means, but his existence is hinted at.

Wrong Number Song
In Room 70 (room_tundra_dock), the northern most part of Snowdin, the protagonist's Cell Phone may randomly get a receiving call. The phone call begins asking for somebody whose name starts with the letter "G", the caller then recognized that they have the wrong number and will then sing the Wrong Number song. This phone call is presumed to be for Gaster, but it could possibly be for Gerson, Glyde, Gyftrot or Grillby instead.

"The Man who Speaks in Hands"
During one of the travels with River Person, they will say to "Beware of The Man who Speaks in Hands." Although, this character states many odd comments, this one in particular sticks out as it is unrelated to the game. This could be a reference to the game show with Mettaton in which Alphys gives the protagonist hints on the answers to the questions from Mettaton, although this is very unlikely because Alphys is a woman.

Some speculate that this could be a reference to his name since it is possible that the W. D. part of his name stands for Wing Dings, a type of font that includes symbols. This is very similar to how the characters Papyrus and Sans are based on fonts. The Wingdings font contains symbols for hands – and supposing that Gaster is based on the font – this could possibly be a reference to him and him speaking in this font, although it is unconfirmed.

Monster Kid
Room 91 (room_water7) is the room that has a bunch of plaques about the monster's tragic history and a small platform which leads to the short dock before the room where Undyne first throws a bunch of spears at the protagonist. On the short dock, a grey version of Monster Kid (spr_mkid_goner) might appear.



The kid wonders about how scary it would be to imagine a world that looks exactly the same, except that they don't exist in it and how the world functions perfectly without them. You can also take an umbrella to them, triggering different dialogue. They soon prompt you to 'forget about them' and disappears when you leave the room they're in.

It's possible that there was a timeline where the Monster Kid had died but was resurrected, presumably by Gaster, to make it possible for the protagonist to escape Undyne. Some have also speculated that Gaster is actually talking through the Kid instead.

Gaster's Followers
Gaster's Followers are grey NPCs that are found near the Elevators in Hotland.

Room 169 (room_fire_elevator_l3) is the room where the protagonist leaves the elevator onto the left part of the third floor of Hotland. If the Fun value is capitalized and set to 62, Gaster Follower 1 (spr_g_follower_1) will appear. This follower is a grey, emotionless version of the NPC normally found licking on the ficus in the restaurant in MTT Resort.

They talk about how Gaster's life was cut short after he fell into one of his creations. They later wonder if Alphys will end up the same way as Gaster. The NPC disappears once the protagonist leaves the room.

Room 156 (room_fire_elevator_r1) is the room where the protagonist finds the first elevator of Hotland. If the Fun value is capitalized and set to 61, Gaster Follower 2 (spr_g_follower_2) will appear. This follower is a grey version on the Donut Guy that can normally be found on the third floor of Hotland in front of the Spider Bake Sale with a talking head coming out of the Donut.

This follower can only speak in rhymes through the face on the item in his hand. They talk about how the old royal scientist, Doctor W. D. Gaster, suddenly vanished without a trace and was shattered across time and space. The NPC immediately disappears once they mention that they are holding a piece of him.

Room 168 (room_fire_elevator_l2) is the room where the protagonist finds the elevator to the left part of the third floor of Hotland. If the Fun value is capitalized and set to 63, Gaster Follower 3 (spr_g_follower_3) will appear. This NPC is talking face coming out of the ground and is not found anywhere else in the game.

They'll talk about how Gaster's life was cut short after an experiment went wrong. They will then stop and mention that they shouldn't gossip about someone who's listening. The NPC disappears once the protagonist leaves the room.

Sans
Sans is presumed to have a large connection with W. D. Gaster due to the workshop hidden in the basement behind Papyrus and Sans's House and his weapons in the Genocide Route.

To access the workshop, one must be at the end of the Pacifist Route and save in the final corridor where Sans explains Execution Points and Level of Violence. The protagonist must speak to Sans repeatedly and reload their save. He will recognize your time travelling powers and grant you a key to his room. Sans's room, after the cutscene with Papyrus when you initially first enter his room is triggered, contains a Silver Key which opens up a room behind their house.

Room 80 (room_tundra_sansbasement) is a workshop that has four drawers and a strange machine covered up with a curtain. One drawer contains a badge and another contains a photo album with a lot of people that the protagonist does not recognize, which later has a picture of Sans, Frisk and their friends if the True Ending was completed. The other two drawers will cause the protagonist to read the blueprint on the countertop, which is said to be written in symbols or handwriting that could potentially be related to W. D. Gaster.

The broken machine in the room has been said to be unfixable according to Toby Fox. Which means that the machine was never meant to be fixed and if this was the creation that Gaster fell in, then Gaster was doomed to remain erased.

Additionally, Sans uses a blaster weapon in the Genocide Route labeled "gasterblaster" indicating that the blasters are a device that was developed by Gaster. An alternate interpretation could be that it was a weapon specifically made to be used against Gaster.

When Sans falls asleep during his battle, his "Z"s are in the font "Aster" rather than Comic Sans.

Quotes
Editing the room number in your save0 and .ini file to Room 264 (room_gaster) will bring up a message that reads the following in the Wingdings font:

"ENTRY NUMBER SEVENTEEN

DARK DARKER YET DARKER THE DARKNESS KEEPS GROWING THE SHADOWS CUTTING DEEPER PHOTON READINGS NEGATIVE THIS NEXT EXPERIMENT SEEMS VERY VERY INTERESTING ... WHAT DO YOU TWO THINK?"

This quote is believed to be the seventeenth entry from the True Lab that cannot be accessed. The "two" mentioned has been speculated to be either Sans and Papyrus, or Toriel and Asgore. The font used, Wingdings, contains hand symbols which could also be a nod to "The Man who Speaks in Hands".

Trivia

 * Attempting to name the protagonist "Gaster" will cause the game to return to the intro; however, you can edit your Undertale.ini file and change the protagonists name to "GASTER", restart the game, and it will run normally. Interestingly enough, entering "GASTER" in Wingdings gives question mark symbols in the .ini file while the game translates the name to "GASTER" (currently unknown if this has any effect).
 * Flowey alludes to Gaster at the start of a Genocide Run, and again when the player travels along the ramparts of New Home. He mentions that someone is watching them. However, during the second time that he talks about this, he goes on to reference people who aren't playing the Genocide Run, but are watching videos of it instead, afraid to do the things the player is about to do.
 * W. D. Gaster is presumed to be a portmanteau of the fonts "Wingdings" and "Aster". Interestingly, while Aster is a font, it is also a suffix in botany which refers to 'denoting incomplete resemblance' between two similar plants. 'Aster' (referred to fully as Asteraceae) is also a family of flowers which includes daisies and sunflowers.
 * Gaster shares some similarities with Uboa from Yume Nikki. This is also shared with Dr. Andonuts from Toby's Earthbound Halloween Hack.
 * Gaster's entry, ENTRY NUMBER SEVENTEEN, is not the only entry labeled 17. Alphys has written a 17th entry, not present in the game, that mentions monsters' inability to handle determination and speaks of them melting together and breaking down. The entry is very similar to Alphys's final remarks in the True Lab before the character exits through the elevator.
 * In Hotland, there's a platform, which is unreachable, on the far right bottom screen, which shows a mysterious, dark figure. Some people have speculated this could be W.D. Gaster.
 * Another possible place W.D. Gaster could be spotted is a room filled with fire and a dark figure appearing in the middle of the room.
 * Based on W.D. Gaster's scary appearance, it could be assumed that after he fell into the creation, he was killed and then turned into a apparition/ghost.
 * It's more strongly hinted that San and Papyrus were the "two" mentioned in Gaster's entry because of the following: After Gaster fell into his creation, Sans and Papyrus wanted to save him, so they brought the machine back to their house, along with his blue prints with the strange font. Also, the shopkeeper states that the two of them had just established there, as if they came out nowhere, which would makes sense why they wanted to find a spot for research and why it's very secret.