Stars are pretty.
Sans decided this while walking around, trying to ignore the clutching sadness and betrayal in his chest. The rainbow soul is his own flickered dimly, making its presence known and making sure Sans knew that it was very upset. But the stout skeleton couldn't respond to its sadness. He wasn't going to apologize, this plan was made a long time ago, and no anomalies would make him go back on the plan, regardless of how they felt. His thoughts only hurt the trapped rainbow soul more as it left an ache in his chest while he proceeded.
"NGAAAH!"
Undyne pounced Sans instantly. "Alright, you lazy PUNK! You're gonna own up to why you're doing this right now!" she roared. "Why did you kill Player-Punk? WHY?" Undyne screamed, spears at the ready. Sans held his hands up in a lazy manner. "Hey, Undyne, chill. I'm just doing what a trusted friend of mine asked…" Sans drawled. "Grrr! You killed someone for a monster trying to destroy reality! Player-Punk never did anything to you!" Undyne growled. "You don't know that," Sans' tone became cold, and a wave of shame built in his chest. He remembered what you did, your soul, complying with the feelings you wanted to feel. "Stop, you idiot. We need him alive, remember?" Flowey growled from below. "Need me alive, huh? What for?" Sans questioned, eyes still dark. "Resetting the timeline, PUNK! Your weird new soul is the one in charge of that, now!" Undyne trumpeted. Flowey bright a vine to his forehead. "IDIOT! You just revealed out plan!" he growled. "Oh, so that's how it's gonna be, huh? Good luck with that," Sans stated before vanishing.
…
Sans could hear Undyne's roars from where had taken a shortcut to. He had gone further than anticipated, considering his new level of power. So, he was the one in charge of the resets, huh? Though, why would the rag tag group of monsters want a reset? And…how did they get free? "Sans, we have something to talk about," Gaster sounded behind him. "Oh. Hey, G. Whatcha wanna talk about?" Sans asked. "I went to check on our prisoners, but all I found was dust, and foot tracks leading through them," Gaster stated. "Why would they kill their way out of that situation…? Unless Flowey went back on his promise…Gh, stupid flower," Sans groaned. Your soul flickered with sadness. "It won't matter after this, once reality has faded, everyone will be safe with me," Gaster told Sans. "You promise they'll be safe in the void with you?" Sans asked. "I assured you before, and I'll assure you again. They will be safe with me," Gaster replied. Sans nodded and the taller skeleton in black vanished.
Suddenly, Sans is surrounded by a crushing darkness. It held on his soul tightly and felt like the darkness was draining the life out of him. It was terrifying, to say the least. All he could see was darkness as it crushed his bones and screams called in the darkness, screams of voices he did not recognize but suffering all the same. The darkness threatened to consume him as a blue light glowed in his direction, bringing him back to reality.
"The hell was that about?" Sans groaned, finding himself on the ground. Was that…one of your memories?! Now he was seeing your memories too?! What in the name of dog was that crushing darkness about?! Was that place the….no, he can't have second thoughts now. He had made up his mind long ago. This had to be done, or the monsters would suffer forever. No other decision would sway him, not even your weird soul's memories. It had to be an illusion. Flowey wasn't the only one in on trying to get Sans to reset. Like that would ever happen, undoing all of this hard work just to go back to an endless cycle of stupid humans playing with their little game until all monsters are all but burned out? Not gonna happen, ever. Sans was solid set on it. Even if it meant bad things happen to those he trusted, there would be no swaying to the other side. He would not get attached, and no one would attach him. Sadness and regret flowed from your crybaby soul, and Sans groaned. It was getting harder to tell his emotions from yours as time went on, but he couldn't relent his control for a second.
…
After Flowey had finished both chewing Undyne out and dodging spears at the same time, the search for Sans continued. The world looked more and more empty as time went on, as blood and bodies scattered the streets. "Egh. At least you don't see the grisly wounds on a terrified monster's face after they die, humans and their physical matter are just gross when they don't turn to dust," Undyne pointed out, poking a body with her spear. "U-Undyne! Wh-what have I told you about saving m-magical energy!" Alphys cried. "Yeah, yeah. We don't know who long the stable magic connection will last in this world and we could get crushed into physical matter and all that," huffed Undyne. "Come on, then. We need to find him before that happens," Flowey urged, continuing on his way.
…
You stared into the monitor of your laptop a while longer. You continued moving Flowey around, trying to find where the stupid skeleton ran off to. You would find him and you would make him reset. It was a near impossible challenge, but you were determined. You would make sure he would pay for what he did to you, even if you would not do it personally. It wouldn't matter how far he ran, or where he could hide, because you would find him. You could find him on the other side of the planet if he decided to go there. But, time was running short.
The void had already begun to consume both worlds, and if it were to finish, you would never be able to get your soul back. You needed Sans to reset, and you would do whatever it takes to do so, even if it mean Sans learning the truth about Gaster the hard way, because you knew he was lying. You knew what the void was actually like. Sans was just a blind puppy following his stupid master around because of how nice he was in the past. Well this is not the past anymore. Blind puppy?
More like blind puppet.