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"You may of never been in control before, but you know who's in control now."
– Gaster when taking over True Fatal's body for the final time

True Fatal Error is an Out!Code created by King Of Videogames. He is the result of Geno learning how to edit a worlds files, giving himself way more DT than before. Thus, he's able to summon anything from any AU, including the human SOULS.


After Geno became Fatal Error, he met a strange man. This man offered a deal to him. In exchange for sharing his body, he will be granted a new power. He accepted the deal. He gained the power to edit the files of any world, and Gaster got to use his body at will. Eventually, after taking control of some of the stronger AUS, along with making friends with ink and dream, they met up with error. They battled him for a long time until they defeated him. Right when they were about to strike their killing blow, some of the other AU's regain consciousness. Though not liking error, they agreed that True fatal was a greater evil, and killed him. That's the end of the story for a while, but a long time later a mysterious being revives true fatal. However, during their time in limbo, Gaster has taken full control and instead of helping this being, he abandons him to destroy the other AUS.



True fatal, though still having bits of the original sans in him, shows no mercy to his victims. Though, some have been able to make friends with him despite his evil. He still has some love for papyrus, but it barely shows. He is scared of CORE Frisk for no apparent reason. His Gaster side shows no mercy and only does things if they believe its justified. They only like Error Sans (on his Gaster side), Classic Sans and Papyrus. They show no emotion, even when destroying AU's like Underswap.


For the most part, he still has the appearance of Geno!Sans. However, the glitch covering his right eye has vanished along with the slash for Chara. He has red in white strings inside of his skull and a large, visible hole on the left side of his skull. His jacket has some small blood stains, though. His gaster form has black goo coming out of his hole and his eyes and mouth, one broken / closed eye on the left, a very ripped jacket with lots more blood on it.

Abilities and Weaknesses

He has lots of determination. He can use not only his own powers, but also Gaster's powers.

  • True Blasters: A combination between last breath's and Fatal's blasters. They can very in size and type. A single one can easily be the size of Omega Flowey. The different types could be the Glitched blasters that spin around, the regular ones that fire in a straight line, orange and yellow attack blasters that have the eye color of the attack, exploding blasters that killer uses, and lots more.
  • Bones: His bones are normally red and white, but there are also his orange and blue bones. He not only has normal bones, but spinning bones, rising bones (like Dusttrust phase 2 type), and many more.
  • Strings: These strings can take over or corrupt a monsters mind to fight for him.
  • Editing the code: This power is his strongest, as it lets him summon any object from NEARLY any AU. Any type of attacks, any type of objects, and any type of monster.
  • Fighting over his mind: Fortunately, he can't fully use these these powers unless either Gaster or himself takes full control of his body.


Error Sans

Error is the whole reason that True Fatal exists, and Fatal's greatest enemy's. Though Gaster sees error differently. Gaster doesn't think killing Error would be smart and instead believes that they should fight alongside error in his quest to destroy the multiverse.


Gaster is the person that shares True Fatal's body in exchange for ultimate power. Even though sharing the same body, they have very different beliefs and cant get along at all. Eventually, Gaster will later take full control of True Fatal's body.

Ink Sans

Ink Sans is a friend of True Fatal's, but not Gaster's. In fact, Gaster hates ink. Ultimately, Fatal is forced to take control of Ink's body as a failed attempt to beat error.

Seraphim Sans

Fatal is forced to take over Seraphim's body to try and defeat error sans.

Core Frisk

True Fatal is terrified of Core Frisk, while Gaster is very interested in them. Not much else to say here.

Classic Sans

He is friends with Sans and enjoys his company. Gaster, though normally violent, also has feelings for Sans.

Classic Papyrus

Though Papyrus doesn't know he exists, True Fatal enjoys watching his long-lost brother.

Error 707 / The Being

Error 707 is the only reason Corrupt Fatal is still alive, but he shows no thanks to him and believes he would of gotten out of limbo on his own.


Art by tsmf829

A picture of True Fatal Error and his unique SOUL. (Art by tsmf829)