Zen!Error

Zen!Error is classical Error!Sans, however, 20 years of being the Destroyer of Worlds has matured him and mellowed his mood. Much of Error's backstory is elaborated upon by the story "Little Talks" which directly begins after the events of the Dreamfalls AU.

After Swap!Sans was kidnapped by Error into the Anti-Void (Events covered by the Ask Error Blog by CrayonQueen), Swap!Sans is rescued by Dream!Sans, who at the time is disguised as a civilian.

Dream is able to get Swap through a portal to the Omega Timeline, but he is captured and briefly held prisoner by Error. Without revealing his true identity, Dream convinces Error to let him go in exchange for friendship. Error dubs him with the name "Sandy" which will stick with him over the next two decades of their secret friendship.

Error reacts negatively to the news of Paper Jam and Gradient's accidental creation (year 2019), threatening Ink that he will kill the children if he ever sees them. However, several years later (2025), Error catches the children getting caught in an AU during a genocide route. Figuring Ink will give him hell, Error rescues them and leaves them in the Anti-Void for Ink to retrieve.

Upon discovery of the AU Fellswap Prodigal, at first Error intends to destroy it like any other AU. But upon realizing the AU is doomed to destroy itself in 18 years, Error leaves the AU be to observe what will happen. In fact, Error wonders what will happen if he can force the AU to survive, and if it will lead to further answers as to why the AUs exist at all. However, Error's experiments with Fellswap Prodigal fail. He ends up rescuing the Papyrus so he can be taken to the Omega Timeline.

Zen!Error also makes an appearance as a team member in The Crashers AU (2030). Five Error characters team up together to travel through Null Space, protecting various multiverses from strange and unusual threats, including the origin species of the Fresh parasite.

Error ends up fostering a skeleton girl named Cambria (2034) who is later adopted by Zhi (Flowerglitch!Papyrus) (2036).

Spoilers:

At the end of the story Tropic Rumble, Error and Dream become a couple (2036), and later get married. (2040)

During the events of the story "Dearest Friend" (2052) Nightmare comes up with an elaborate plot to get himself killed. And because his soul is directly linked to Dream's in JumpVerse, this also causes Dream's death. So grieved by his husband's death, Error uses all his magic and Dream's dust to create their daughter Trial.

Trial's creation is discovered by Gradient, and Error dies in Gradient's arms soon after, unable to recover from the trauma of Dream's death and the use of so much magic.

Ink and Dream's family both planned to bury Error's dust along with what was left of Dream's together in the same memorial and in a newly built mortuary temple in the Dreamfalls. However, rumor quickly spread throughout the multiverse that Error murdered Dream, so a separate memorial for Error had been built to prevent outrage.

As such, Error's memorial would be vandalized over several years, until the Inkkins and Dreamkins discovered the truth of Nightmare's plan to get himself killed, along with Dream. (2059) This information finally allowed the families to move Error's dust into the same memorial with Dream.