|“||I'm sorry THEY involved you in this. It's THEIR fault, not yours||„|
|~ Core!Frisk talking to Sans|
Core!Frisk is a supporting character in Underverse, and a minor one in The Truce. They're strangely mysterious and enigmatic, as Core!Frisk will appear and disappear at their own will. They are, however, opposed to The X-Event, as they give Sans some helpful advice to defeat Cross and free the souls corrupted by the X-Event.
As Error!Sans starts attacking Ink!Sans, Core!Frisk watches from afar, and after the two are teleported to that island, they wonder where they went, and questioned if they have ceased to exist at all.
One day, Cross comes up to Ink, and tells him that Core!Frisk tried to get him someplace safer for people within a genocide run. He refused, stating that his world still existed.
After fleeing the scene in Underfell's Snowdin, Sans gets a helpful advice from Core!Frisk, telling them to distract Cross while he can, which will allow him to free the corrupted souls. They apologized to him regarding his involvement, and leaves once Underfell!Sans arrives.
Core!Frisk is first seen in the ruins of the shattered Underswap timeline. They ask Underswap!Papyrus why he didn't go with the others, as well as explaining that they can't take him to the Omega Timeline. Underswap!Papyrus responds by saying that he can't live in the world anymore, and that he didn't want to see his brother die in front of his eyes. He eventually glitches so much that he leaves existence entirely along with Underswap!Chara. Noticing this, Core!Frisk begins to cry, noting that the two did everything to save their timeline before being approached by X-Tale!Alphys, who says nothing to them but instead mentions details about the current Underswap timeline, noting that there wasn't anything left.
Core!Frisk watches as X-Tale!Alphys places a piece of paper on the ground, which then begins to send out waves of energy around it until the entire landscape was completely white. Core!Frisk notes that what X-Tale!Alphys executed was a quarantine, which, according to them, will prevent the Alternate Universe and any of its timelines from being corrupted. Core!Frisk then follows X-Tale!Alphys to her next destination, which is the Underfell timeline that Cross took Snowdin from.
Core!Frisk watches as X-Tale!Alphys and X-Tale!Mettaton fight Underfell!Asgore. They look away before suddenly being in X-Tale along with Dream!Sans. After a small conversation between the two, Core!Frisk reassures him that everything Cross did to the timelines will end very soon.
They are also shown watching for a as Ink brings XGaster back, despite being elsewhere. This is because of their omnipresence in the multiverse, however.
Core!Frisk also appears at the very end of the episode during the credits sequence, waiting for Cross in the Omega Timeline.
Core!Frisk is a monochromatic child, with empty void sockets instead of eyes. They wear a shirt with gray and white stripes, black shorts, and black shoes.
Core!Frisk is omnipresent, meaning they can see everything in the existence. They can appear at any place at any time they wish, however because of the nature of timelines and how they split, the probability of physical appearance is only 50%. This does NOT relate to Frisk's ability to see all.
Frisk appears to be rather expressionless and distant, at time even condescending towards the conflicts and people actively involved in them, calling Error and Ink "immature" as the two fight in the distance. They however seem to care for the characters' well-being, inviting Cross to the Omega Timeline (note: a sanctuary timeline) and giving Sans some helpful advice.
- Despite their all-seeing power, Frisk is visibly confused when Error and Ink are relocated in The Truce. Even assuming they're for some reason unable to observe the destination, it doesn't explain why they cannot observe the future of their return.
- Despite their benevolent nature, Frisk gives Sans an advice on how to defeat Cross rather than tell him how to save everyone.
| 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