Popular Undertale Fan Theories

Since its original release back in 2015, Undertale has become a global phenomenon, especially in many circles of the online community. Toby Fox managed to create a truly unique and innovative video game that has been praised for a variety of reasons, like its story, its mechanics, and its characters. However, the world and lore of this game remain one of the game’s most intriguing aspects.

The words Undertale and “theory” basically go hand-in-hand, especially since Toby Fox intentionally left a lot of mysteries and unanswered questions in this bizarre adventure. This game spawned a huge community of fans who have formulated their own theories in their search for answers, and these are some of the most popular ones.

7 Frisk Is A Monster

The Protagonist’s Real Identity

The main character of Undertale is a young child known as Frisk, who saves (or destroys) the underground thanks to their overwhelming determination. The monsters and the humans had been divided for many years at that point, so the fact that a human child managed to unite them was a big deal.

However, many fans noticed that, even though most monsters in Undertale are supposed to fear or hate humans, almost none of them acknowledge Frisk as one. Coupled with their surprisingly powerful determination, this led to the popular theory that Frisk may actually be a monster with a human-like appearance.

6 Sans Is A Human

Maybe Frisk Is Not Alone

Going in the completely opposite direction, there’s another theory regarding Sans, the funny skeleton who has become one of Undertale’s most iconic characters. This theory proposes the idea that Sans is not actually a monster, but a human in disguise who has been watching Frisk all along.

Sans is supposed to be a skeleton but, unlike his brother Papyrus, he doesn’t really show his bones at any point in the game. His design also looks off in comparison to other monsters in the game. Because of this, many fans believe that Sans is a human who’s wearing a skeleton disguise. If this is true, however, it is most likely he was part of some sort of scientific experiment that made him as powerful as he is now.

5 The Six Humans Are Alive

Where Are They?

One of Undertale’s most intriguing mysteries is the fate of the six humans whose souls were taken by Asgore Dreemur. While humans can’t usually live without their souls, in Deltarune we see human protagonist Kris temporarily ripping his soul from his body without dying. So what if something similar happened to these humans?

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This theory is also enhanced by the fact that, near the end of the game, the player can find the open coffins of the six humans. Where are their bodies? Where did their souls go? Maybe it’s possible that they returned to their bodies, and managed to escape the Underground after all. Although Flowey says that Toriel may have given them a proper burial, many fans still hope they were revived, because it would give a bittersweet ending to one of the game’s darkest plot points.

4 The Six Humans Were Reincarnated As Monsters

They Were Here After All

As is common with the lore of Undertale, there is more than just one theory regarding the whereabouts of the six humans, and one of the most interesting ones is that, instead of dying, their souls slowly took new forms and eventually were reincarnated as characters that are based on undead monsters (like skeletons, ghosts, etc.)

This theory proposes that Sans has the blue soul of integrity, Papyrus has the green soul of kindness, Napstablook has the cyan soul of patience, Mettaton has the orange soul of bravery, Mad Dummy has the yellow soul of justice, and W.D. Gaster has the purple soul of perseverance. This would make sense considering that these traits actually go along with each character’s personality, not to mention that it would add a layer of depth to these beloved monsters.

3 The Secret Of The CORE

What’s Inside There?

The CORE is one of the most intriguing locations in the game. Even though, at first, this seems like a harmless technological facility whose main purpose is to provide magical electricity to the entire Underground, once the player dives into its background, they’ll quickly find out that it holds some secrets and mysteries.

It is heavily implied that W.D. Gaster is the creator of the CORE, and that he may have fallen into his own invention. So, maybe his body is still there, somehow affecting this technology in some unexpected way. There are many other theories about this place, like the one that says the soul of Chara is inside the CORE, powering up the underground with their huge amount of determination.

The Third Font Skeleton

W.D. Gaster is one of the most puzzling figures in all of Undertale, as he’s a character that some players may not even encounter at all. Even if they missed him in the game, players have definitely heard of him, seeing that he’s one of the fan base’s favorite characters and the subject of a lot of different theories. The most popular is one that tries to determine his relationship with the game’s other two skeletons.

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Since Gaster seems to have a skeletal appearance and almost every piece of text related to him that can be found is written in the font Wingdings, many fans believe that he’s most likely related to Sans and Papyrus, who are also skeletons named after popular fonts. This theory has many variations. Some think Gaster is actually the other skeletons’ father, or that he was split into two when he fell into the CORE, with the skeleton brothers being his two remaining halves.

1 The Connection Between Undertale And Deltarune

Is It Truly An Alternate Universe?

Despite its huge success, Undertale never received a true sequel. That said, in 2018, fans were surprised when Toby Fox announced and released Deltarune, a spiritual successor that clearly used a lot of the same mechanics and themes. The biggest surprise, however, was the fact that many beloved Undertale characters can be found in the world of Deltarune, like Sans, Alphys, Toriel, etc.

Toby Fox has confirmed that this is just an alternate universe with new versions of these characters, but it is not really connected to his previous game. That hasn’t stopped fans from formulating theories about how these two titles are connected. Some believe that, within the world of Deltarune, the events of Undertale are completely fictional.

Maybe Undertale was Kris’ dream all along. Or it was a play that Kris & their classmates had to perform at school. Or was it the plot of their Dungeons & Dragons campaign? There are many possibilities, and fans will receive answers when more chapters of Deltarune are released in the near future.

Undertale

Released

September 15, 2015

Developer(s)

Toby Fox