Undertale Souls Guide

Undertale Souls Guide

Souls play a considerable part in the narrative of Undertale. It’s explained that your human soul is what makes you unique. Your soul is stronger than the monster’s souls, and human souls are needed to break the Barrier separating the Underground from the surface.

In every route you can take in Undertale, the soul plays a role in the story. The Monsters want to take your soul. Even Chara wants your soul.

Let’s get a few details out of the way first before we go into our complete Undertale Souls guide.

Undertale: Shape Your Destiny Beneath the Surface | GOG

Embark on an unforgettable journey through the underground world of Undertale, where every choice you make shapes the fate of monsters and humans alike. With its charming retro graphics and innovative gameplay mechanics, immerse yourself in a tale of friendship, determination, and the power of mercy.

Check Price Buy at GOG
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Key Details Up Front

The soul isn’t a character, but some characters have one, which is why Asgore and the other bosses attack you.

  • Character Type: Plot Mechanic
  • Difficulty: N/A
  • First Encounter: You first learn about your soul when you meet Flowery.
  • Optional: No
  • Personality: This depends on how you want to play the game.
  • Skills: Depending on the color of your soul, it will behave differently. I’ll get more into this in the description.


While your soul is what the bosses are after, it also appears in battle scenes. When you first meet Flowery, he takes you to a battle and tries to kill you. Flowery tells you that the little red heart is your soul, and you can move it around to avoid attacks.

A human soul can be changed into one of seven different colors; each has its gameplay mechanics. I’ll go more into this later. A monster’s soul appears as a white upside-down heart.

You can see a human soul during every battle. The monster’s soul doesn’t appear as often. The two times that I know of are when Toriel and Asgore are killed and turn to dust, then again when Asriel returns the souls to the other monsters.

Some monsters seem to be able to absorb the souls of humans. It’s not clear if any monster can do this. Flowery and Asriel seem to be able to, so I’m guessing that both Asgore and Toriel can.

This was one of the times that I got a bit confused about the powers of the characters in Undertale. It seemed a bit ill-defined at times. Asriel, and later on Flowery, seem to be able to absorb and release the souls of humans and monsters at will.

Let’s talk about some of the Key Moments where souls are brought up and are used in combat.

Continue reading our complete Asriel guide.

Key Moments

Souls play a big part in the story of Undertale. A few times, souls get explained or are used as a plot device. This will get into the endings a bit, and there might be some overlap with other articles.

Here are a few times that I think explain the role that souls play in the game.

Meeting Flowery

You learn a lot about souls and how they work in the game from Flowery. He is the first character you meet, and he seems to influence the game from behind the scenes. This is also where you learn more about souls and their role in battle.

Sure, Flowery tries to kill you and claim your soul early on, but he teaches you how to play the game. It’s not all bad. Okay, he is evil and wants to take the souls of all the monsters as well.

Papyrus Turns You Blue

You get warned about this by Sans. He tells you about Blue attacks and how you can avoid them. You also get warned about the special attack that Papyrus has.

It’s a little misleading. You have the blue attacks, where you stay still, and the attack can’t hurt you, and you have Papyrus turning your soul blue. With Papyrus turning you blue, you enter a jumping mode during the battle scene.

By pressing a button, you can jump, just like a platformer. This is supposed to act like gravity. I kind of like this when compared to the other modes. This one seems to make more sense to me when I would play.

Depending on the ending you’re going for, this mechanic can be fun or a waste of time. You can not touch the jump button and let Papyrus defeat you.

Undyne Turns You Green

I like the way the developers did this one. Undyne tells you how to get past her if you don’t want to do the Genocide route. She tells you that while you’re Green, you can’t escape. So, you have to wait for your soul to turn Red again.

I didn’t realize it right away on my first playthrough. However, I figured out how the game wanted me to play.

When you’re Green, you can’t move around. You have a shield that you can angle to block Undyne’s attacks. After a few rounds of attacks, Undyne will turn you back to Red, and you can run away from the fight.

Muffet Turns You Purple

This is my least favorite fight in the game, and it’s avoidable. When you get trapped by Muffet, she will turn you Purple. In this mode, your movement is restricted.

You can only move horizontally and vertically on a grid. It reminded me of playing Frogger or some other arcade game.

Dr. Alphys Turns You Yellow and Lets You Shoot Stuff

This one was a little strange for me. Dr. Alphys can somehow manipulate your soul and turn it into a spaceship-like thing. This was one of the parts of the game that I thought was a bit too strange.

Up until this point, things make sense to me, or at the very least felt like they belonged in the world of Undertale. This felt a bit off. I liked that you could shoot at stuff during the fights with Mettaton, but it felt a bit too strange to me.

True Pacifist Ending

With the ending here, you fight a few versions of Asriel. It starts with Flowery, who tells you that he has absorbed the human souls which Asgore had collected. As the battle goes on, he absorbs the souls of the monsters and turns into Asriel.

There is a lot that goes on in this fight. The part that matters for us is that you save the souls of those that Asriel had absorbed. Once this is done, you can save Asriel’s soul and return him to his child form.

Asriel explains that with all of the monster’s souls, he could feel the love they have for our main character. He returns the souls he absorbed, and we move into the epilogue.

I like how the importance of a soul and being good is brought full circle here. When I first played this, I was playing like every other RPG. When I played the True Pacifist route, things like the soul made more sense.

Genocide Ending

You get to this ending by killing everything that you fight. It’s implied that this taints your soul and turns you evil.

Once you have reached the end of this path, you meet Chara. She gives you some explanation of what happened and how you have affected the world. She also gives you the option of erasing this version of the world.

This is where you can give Chara your soul. By doing this, you can play the game over. However, the endings are changed to match that your character has given up your soul. I like how the developers did this.

It’s an essentially permanent change that reflects how your soul can’t be good anymore. You can’t get the True Pacifist ending unless you get a mod or something else.

Mechanics of Each Soul

Your soul can change color during boss fights. This is usually connected to how you should beat the boss or a battle mechanic introduced earlier. You can also find hints by talking to the characters.

Here are some of the colors that your soul can get changed into:

  • Red – Normal mode
  • Light Blue – Stay still, and the attack won’t hurt you
  • Orange – Move through the attack to avoid damage
  • Blue – Gravity is increased, making it hard to move. You see this while fighting Papyrus.
  • Purple – Restricts you to a horizontal movement. You see this while fighting Moffet.
  • Green – This comes up on two occasions. Undyne turns you Green to keep you from running away, and you also see in some battles where you are supposed to touch the Green attacks.
  • Yellow – This one is a lot of fun! It turns your heart into a ship, like Space Invaders or Galaga. This mode comes up during the Mettaton fight.
  • Blue/Red – This only appears in the Nintendo Switch version of the game. I didn’t play this version, but I wanted to mention it.

These get introduced as you make your way through the game. They also affect the battles leading up to the bosses, and some have roles in the puzzles you have to solve.

Key relationships

A few characters have more to do with souls than the rest of those in the game. Specifically, the main character, Asriel, Chara, and Flowery, do more with souls.


This is the character that you play in Undertale. It’s Frisk’s soul that is the center of the game. It’s used in all battles, and it’s what the bosses are after.

The monsters, specifically Asgore, need your soul so they can break the barrier that separates our world from the underground. Flowery also wants it for the same reason. You can also give your soul to Chara at the end of a Genocide route.

Chara and Asriel

Image from Fandom

You find out a lot about Chara the more you play Undertale. The big thing for me was Chara’s role in creating Flowery. As a human, she also had a more powerful soul and could pass through the Barrier.

When Chara died, Asriel absorbed her soul and passed through the barrier. From there, Asriel ends up dying while still possessing Chara’s soul. His ashes get spread over a flower bed, and the two of them form Flowery.

In the True Pacifist ending, you find out more about Asriel’s connection to souls and how he can absorb them. Asriel can absorb both human and monster souls. He can also do this as Flowery.

I also think that Asriel was affected by Chara’s soul. It’s mentioned that Chara is evil, and I believe that Asriel was changed into an evil version of himself by absorbing Chara’s soul.

At the end of the Genocide Route, Chara asks for your soul in exchange for resetting the world so you can play again. It’s an excellent idea that I like a lot.


Image from Fandom

Flowery is the reincarnation of Asriel. He came to be after Asriel absorbed Chara’s soul, then died, and had his ashes spread over a flower bed. This caused Flowery to lose the ability to feel love, turning him into evil.

He seems to have the ability to absorb human souls and turn back into Asriel. I’m not totally sure what Flowery’s end game was. He was trying to break the barrier because that was the original plan that Chara and Asriel had.

It’s hard for me to separate Flowery, Asriel, and Chara. They’re all connected through their souls. Each of them plays a big part in the plot of Undertale.


Here are some quotes about souls and the bosses turning your souls a different color.

“You’re blue. That’s my attack!”

Papyrus says this when you first face him. He isn’t the best with words, and I think he could use some help from Sans on the one-liners.

“As long as you’re green you can’t escape. Unless you learn to face the danger head-on… You won’t last a second against me!”

Undyne says this during the neutral route when you first fight her. This one is a fascinating mechanic, and it tells you that you have to hold out until you can try to escape unless you go the genocide route.

“I think purple is a better look on you!”

Muffet says this on her first turn. You can avoid this fight by buying and eating one of the Spider pastries from the bake sale in the Hotlands or the Ruins.

“See that heart? That is your soul, the very culmination of your being!”

Flowery says this to you at the beginning of the game. It’s a way to explain how the battles work. You move your soul around to avoid the enemy attacks. It’s also a way for the game to tell you how important souls will be to the story.


Question: What is a Grey Soul?

Answer: A grey soul is a weakened soul. This is what the monsters have. I think it’s just another way to distinguish them from you and point out how unique a human’s soul is.

Question: What are Blue and Orange attacks?

Answer: A blue attack is one that you want to stand still for. That way, they won’t hit you. An orange attack is the opposite of a blue. You want to be moving to avoid damage. You’ll also see these in the Hotlands when you go from puzzle to puzzle.

Question: What is a Green attack?

Answer: The green attack is one that you want to run into. You encounter these a few times. The ones that come to mind are when fighting a Woshua and a Tsunderplane. By running into the green attacks, you can end the battle peacefully. They usually have a specific number of times you have to run into them.

Question: What is a Red attack?

Answer: A red attack normally doesn’t do damage and is used to warn the player of an upcoming attack. Bosses usually use this.


Souls are one of the interesting parts of the game. Everything is designed around them, and they play a big part in the game’s plot. I like the way that the developer set all of this up.

Mechanics are introduced through fights with random monsters, and then they are expanded on in the boss fights. The souls in the game are introduced, and their importance is reinforced as the game goes on.

Their role in the plot gets a little confusing. It makes the story a bit manic if you only play the game once. However, it makes more sense once you play each route and find some of the easter eggs.

Undertale: Shape Your Destiny Beneath the Surface | GOG

Embark on an unforgettable journey through the underground world of Undertale, where every choice you make shapes the fate of monsters and humans alike. With its charming retro graphics and innovative gameplay mechanics, immerse yourself in a tale of friendship, determination, and the power of mercy.

Check Price Buy at GOG
We earn a commission if you make a purchase, at no additional cost to you.
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