|“||HUMM...THIS PLACE IS PRETTY BIG FOR A SINGLE PERSON. THIS IS KINDA SELFISH Y'KNOW?||„|
|~ Error!Sans after he ties up Cross|
Error!Sans is a major character in Underverse. With both him and Ink!Sans deprived of fighting each other, Error sternly tells Ink not to create anymore and that he won't destroy anything. With the X-Event headed on its loose end, Error sees the truce he created did nothing to stop Ink, and ends it off shortly after his discovery.
With half of the multiverse gone, Error!Sans takes this tied battle as his own gamble against Ink. He forces Ink to abide by his truce of having no more creation and destruction.
One day, while waiting for Ink to come back, Cross is surprised by Error's appearance. He takes his soul, and once Ink arrives, Error tells him he can't save him. Telling him to stop, Error fires his blasters on Cross; Ink gets the hit instead when he frees him from Error's string. His soul, however, is now stolen, and with that, both Cross and Cross!Chara are fighting for control; they leave Ink injured.
After the fight against Cross, Ink is pulled over by Error, who alerts him that he still has Cross's original soul because of the truce, and bluntly tells him that he'll have fun if he finds out that he broke the truce.
While he takes a break from finding the Omega Timeline, Ink arrives in Error's world, telling him he had a long day, and needed a break before he overthrows him. The two watch Undernovela, but as it continue, Error notices that Cross had entered the AU, taking Undernovela!Frisk in order for Cross!Chara to have a human soul. Once Asgoro and Sins barges to save the day, the two are met by Ink, who uses his vial to erase the pair. Ink gratefully thanks Error for joining his game, and as soon as he wakes up, he enters the Doodle Sphere and proceeded to tie up all the AUs.
He enters X-Tale when he glanced towards its page, not aware that Fresh had also made it here as well, protecting it from outsiders like him until Ink "comes back". While Fresh provided him the details that Ink had left for Underswap, Error is stunned by the fact that Underfell's Snowdin and Underswap's characters had landed in this AU. Knowing it was all Ink's doing, he officially proclaimed that the truce was over.
Error first appeared in Outertale when Nightmare was trying to convince X-Event!Chara to take a soul of the monster that Killer!Sans had killed. He taunts them, showing them Cross' captured soul. After a remark from Nightmare, he puts the soul away and appears calm at first, but then breaks out in a rage, demanding Nightmare to tell him where Ink is, to which he responds that, since Ink isn't taking his vials anymore, he can't detect his presence.
Later, after Underfell!Sans asks what Classic!Sans did to get him all panicked, Error tells him that it was none of their business before proceeding to tie up Classic!Sans, Underfell!Sans, and Underswap!Sans' souls in his strings.
After Ink arrives, Error tells him that he is going to destroy his "stupid anomaly friends", to which Ink replies that they are not his friends. While Ink was explaining his plan with his friend's soul, Error grows extremely annoyed by Ink's actions and knocks the vial out of Ink's hand, taking it away and storing it high in the air with his strings.
During his fight with Ink, Error uses Classic!Sans, Underfell!Sans, and Underswap!Sans in order to attack Ink, even if it only lasted for a moment. During Ink's explanation about the multiverse and its universes, Error exclaims that he shouldn't have negotiated anything with Ink. After XGaster's reawakening, Error tells Ink that he is glad to know how scared he is of him before telling XGaster that he won't join his game and destroying all of the multiverse sheets in the Doodle Sphere. Once it's all over, Ink uses his paintbrush to tie Error up in strings before sending him back to his anti-void, XGaster breaking in to take the soul that Error had stolen from Cross.
Before Xtra Scene 1, his appearance is similar to a Sans; his head is completely black, with blue streams running from his eyes, which his scleras are red, his comea are yellow, and his pupils are blue. His exposed legs are red, his slippers, pants, and jacket are in blue, yellow, and black, and his fingers are yellow. With the advent of Lucidia, he was redesigned to match that of Lucidia. His pants and jacket now feature blue stitches, and he now has a scarf, which Ink seems to like when he first encounters this design. Both design both feature the word "ERROR" all around him, with some minor glitching included.
Error!Sans can not only fire Gaster Blasters at his will, but can shoot out strings to tie up his victim. These strings can be used to extract the souls of the victim itself. He's even able to destroy AUs, but as of Underverse 0.3, he's not able to perform that feature due to the truce.
Error may have a sensitive feeling towards others, but he's often shown to be remorseless, wanting to destroy all the AUs Ink cared so much. Even though the truce was made, Error still had a negative feeling with Ink, especially when he started talking about his new friend. He even extracts Cross's soul without Ink's consent, but he still decided to keep it intact to stay loyal with the truce. Once he makes the discovery, though, he feels confident that he'll beat Ink and destroy his precious AUs.
| X-Tale: Cross | X-Event!Chara | X-Event!Frisk | XGaster | X-Tale!Papyrus | X-Tale!Undyne | X-Tale!Toriel | X-Tale!Asgore | X-Tale!Asriel | X-Tale!Mettaton | X-Tale!Alphys