OVERWRITE

OVERWRITE
Abilities	The ability to change everything within a timeline.
Users	XGaster X-Event!Frisk X-Event!Chara

"This is what has ruined our world ten times. I'm tired...but I'm forced to use this power"

— X-Event!Frisk explaining to XTale!Sans what's happening with his world

OVERWRITE is a very powerful tool, designed to modify the course of a timeline. It works with a tap of its button; it'll allow any user to change the reality of a timeline, as well as any thoughts, actions, memories, and roles. . However, its power is extremely abusive, which allows one to continuously change reality at will without any care to its inhabitants.

OVERWRITE is fairly limited though. With only half of the ability, one cannot overwrite an AU, nor the multiverse itself. It can only corrupt one timeline, and the code that follows, and is not guaranteed to be permanent. The RESET ability also makes any OVERWRITING null, since it reverts any changes made with the OVERWRITE button. Also, overwriting anything without a specific code, or an original character is impossible to do so. It can also be broken by a user but this is only possible by the current user.

The three main users, XGaster, X-Event!Frisk, and X-Event!Chara, all use it for different purposes: XGaster uses the OVERWRITE button on the basis to attempt to garner a perfect story, while X-Event!Frisk and X-Event!Chara attempt to use the button in order to freed themselves and their friends from XGaster's grasp. Although Cross has the ability to use some of the X-Event's power, he does not have full control over the Overwrite button; this is due to the button only working when 50% of their HP is from the owner's race. In this case, the owner of the OVERWRITE button that XGaster grants to are two humans.

X-Event!Chara also had no control over the OVERWRITE button after X-Event!Frisk's death unless he is able to provision his soul to obtain enough HP from a human, which he does find with Underswap!Chara by absorbing 95% of their HP. He ends up losing access to the button as their HP depletes thanks to Nightmare!Sans killing Underswap!Chara and XGaster quarantining the Underswap timeline. This was also the reason he strongly demanded Ink!Sans and later Nightmare!Sans to give him XGaster's portion of his soul, to try to own the complete OVERWRITE button.

Currently, the OVERWRITE button is in full form under XGaster, having his soul unified once more thanks to Ink!Sans' promise to keep his other half safeguarded from the X-Event.

Extra info

The OVERWRITE button was presumably created by XGaster.