It was a beautiful day, one that had been covered by the dust of many monsters had lost their lives to the whims of a single child. The birds were singing, however, their song was now muffled by the sound of multiple Gaster Blaster firing one after the other in quick succession, followed shortly by the sound of a body being repeatedly slammed on the walls, floor and ceiling of the corridor until eventually everything became dead silent.
And there they were, lying down on the ground, barely clinging on to their life, their body badly bruised and burned. It was a struggle to even look in the direction of their attacker, a skeleton that had gone through completely unharmed, but seemed to be on the brink of passing out due to exhaustion, only managing enough energy to talk.
They heard him ramble on and on, trying to get them to give up and go back on everything they had done so far. Eventually, the exhaustion caught up with him and he began falling asleep. Once he did, the child slowly began to stand up again.
"I can't believe he fell asleep at a time like this…" thought the child, surprised
A wicked smile made it's way into the child's expression "Heh, dying while sleeping is going to be a fitting end for him," said another voice within the child's head.
Keeping a firm grip on the knife they had in hand, they began walking towards the sleeping skeleton, but as soon as they took the first step, they stopped, not on purpose, but more like a force halted them.
"... Chara… Why are we doing this?" The child asked, sounding hesitant "Why are we killing everyone like that? Even monsters who did nothing to us…"
"What? It was you who started all of this, don't you remember, Frisk?" Chara replied, letting out a couple of chuckles "At first I had no control over what you did, in the beginning it was you who killed those monsters, all out of a sense of self-preservation, all I'm doing is finishing the job for you."
They took another step forward, before stopping again.
"I-I don't want to do this anymore… I want to go back, I want to fix everything…" said Frisk, their voice almost breaking as they wanted to start crying.
"It's too late for that now. You're not the one in control anymore. All that killing, every single death, it made me feel stronger, it made me feel… alive." Chara then began giggling "And I won't let you take that away from me now. Besides, I really want to know…" they then focused their gaze on Sans "just how much EXP that comedian is worth!"
"Wait, stop!"
Chara then rushed forward ready to strike at Sans to deal the killing slash. However, it turned out that Sans wasn't quite done yet as he quickly sidestepped out of the way of the attack.
"Heh, didja really think you would be able- huh?"
Sans looked at the kid as it turned out that, in reality, even if he hadn't moved out of the way the attack wouldn't have hit him as the kid had stopped right in front of him, the knife they were holding raised up. Their hand was shaking, as if there was some kind of internal struggle going on. He first thought he could use that opportunity to kill them, but he was too tired to summon even a single bone so all he could do was watch.
"W-What?! How did you-" said Chara, sounding just as furious as they were shocked
"I'm not going to let you keep doing this, it's time to stop!" Frisk then made use of the opportunity to simply toss the knife away as far as they could. "The determination that has gotten us so far, it's all mine. So I'm going to use that same determination to stop you now!"
"You-! You're ruining everything!" Chara yelled.
"Hey, kid… what's up with you?" Sans asked, obviously having no clue about what was going on and being afraid of getting any closer
Frisk then turned to meet Sans's gaze, showing that tears were streaming down their face, tears that clearly showed regret. Not only that, but their body was shaking with the struggle for dominance that was going on inside them since, as much as Frisk wished they could have full control now, Chara's influence was still really strong and if they faltered even for just a moment then it would be all over, though at least now they didn't have a weapon.
"S-Sans…" said Frisk, their voice sounding like they were in great pain, both from the wounds from the fight and also the struggle with Chara, "I'm so sorry."
"Huh?"
"I-I'll fix everything, I'll go back and-" Frisk then almost collapsed, just barely managing to strength to keep resisting "I'll bring everybody back, I promise!"
"NO! YOU CAN'T RESET!" Chara shouted, starting to sound desperate.
Sans was simply dumbfounded, the kid was now acting like a completely different person. Even though he thought that it was all an act at first, the tears, the expression of regret and the pained voice… It was all too sincere to be just an act. Seeing all of that, Sans could help but relax and sigh in both relief and disbelief.
"So, in the end, even you could change for the better… i guess papyrus's faith wasn't misplaced after all" said Sans, closing his eyes for a moment, looking completely at peace. Once he opened his eyes again, his expression had changed to that of pity towards the beaten down kid that could barely stand upright, "all right, kid, i'll trust you, just this once."
He then walked towards the kid and pulled them into a hug. At first, Frisk was shocked, but at the same time… Knowing that Sans, even after everything they had done, could still bring himself to make such an act of kindness towards them… It made all the pain start to fade away and being replaced with warmth. They could feel themselves being able to resist Chara's attempts to take over more easily as they were filled with determination.
Frisk began crying even more intensely on Sans' coat as they hugged him back. "I promise that once I go back I won't kill anyone and... I'll set you all free and then… then..." Frisk managed to give a small, sad smile that was also filled with hope. "Then we can all be friends right?"
Sans then let go of Frisk and gave them a pat on the head "yeah, i would like that," he said, then giving Frisk a wink "so yeah, get outta here. I kinda want to see everyone alive again."
Frisk gave a solemn nod and stretched their hand a little. A small rectangular button with "reset" written on it showed up in front of their hand. They looked at it for a moment, before looking back at Sans with a peaceful smile.
"See you soon."
"STOP!"
Chara was trying their hardest to prevent Frisk to press the button, but at this point there was just not stopping the kid, they were far too determined to save everyone now. With a final approving nod from Sans, Frisk pressed the button.
Everything began to rewind at such an incredible speed that Frisk could barely tell what was happening, in the blink of an eye they found themselves staring up at the top the hole they had fallen through. They could still see the light coming up from above and they could feel the golden flowers that served as a bed for them. There was no pain anymore and Chara was silent, it was an all-new beginning.
They sat up, staring at the flowers under them. They took a moment to let it all sink in before letting out a long sigh of relief.
"Chara… You're still there?"
"Why." Chara said in a very anguished tone "Why does everyone betray me like that?! We were so close and… and… you just ruined everything!"
Frisk sighed. "It was because of me that you got like that, by killing monsters you just got more and more unhinged… I want to save everyone, and that includes you as well."
There was silence, absolutely no sound as Frisk just remained seated on the flowers, waiting for a response from Chara. Eventually, they responded with a chuckle
"Good luck with that. I don't care about what happens now that I'm not in control. You, humans, monsters… You should all just die already," they answered, the bitterness in their voice being almost overwhelming.
Frisk then stood up and stared at the corridor that would led them further into the Underground. They began thinking back to the question Sans had asked them back when they first had entered that one corridor
"Do you think even the worst person can change...? That everyone can be a good person, if they just try?"
Papyrus had believed in them even when they murdered him in cold-blood, all because he thought he thought they just needed guidance. Maybe he wasn't wrong and that was all Chara really needed, someone to show them the right way towards a brighter future, where they could stop being so bitter and become a better person.
If even the worst person could change, then surely Chara could as well.