This is a fanfic based on Undertale (number 3)
It will be told in various points of view, primarliy Chara and Asriel Dreamurr. If it switches to a new POV, I'll make it known beforehand :)
This fanfic is actually a collab between me and dream1990.
With this out of the way, let's begin:

Sans POV:

it had been a long and arduous thing that i was forced to live over and over and over again. every time that Frisk came through the underground, he would either save everyone or kill everyone. and it all started from one single point in time. when Asriel and Chara's plan went totally wrong. so, when i found this out, i started to do some investigating into the timelines, as the injection of Determination i received from alphys gave me slight powers over space and time. the only problem is that i knew not to try and go back in time on my own, as it would be impossible for me to save the timeline on my own. i needed to finish the machine that Gaster left in my workshop before his disappearance.

"okay, it should be just about finished... never thought i'd say those words in my entire existence..." i said with a sigh. today was one of the days where frisk would start over their journey, so i took at least 50 minutes every time this happened to try and fix up the machine. for some very odd reason, the machine's updates and working functions were not affected by the resetting of the timelines. but today, after the 109th pacifist run... and after 200 genocide runs... i finally was nearing the final phases for the machine to be completed. i needed to complete it within the next 10 minutes, since after that, i'd need to get over to the door to the ruins to wait for frisk to show up.

"alright, Gaster... time to finally decipher this language you came up with..." i said with seriousness and Determination, reading the final bits of the instructions on the machine, which i'd been deciphering bit by bit. Gaster used to be the royal scientist, but he disappeared shortly after the first human soul was captured by Asgore. and his way of encrypting his codes and instructions was very well-done. it was all a matter of trying to decipher the words that were turned into pictures on the instructions. i then deciphered the instructions and found that i needed to do one final thing to the machine. i needed an alarm clock to finish the job. i then warped directly to my room and grabbed the alarm clock i had by my bedside. once i did so, i warped back to the machine and proceeded to put the finishing touches to it. and the clock said that i had 5 minutes left just as i finished up.

"the moment of truth... i hope this works," i frowned as i pushed the button on the side of the machine and it hummed to life, me gawking at how it worked effortlessly! it was finally ready! "okay, now to just step inside and put in the date and time," i smiled as i entered the machine and put in the time, date, and coordinates. the day was set for 2 weeks after Chara had fallen into the underground, March 14th, 201X. i chose that day because it was when Chara was used to seeing monsters and after she had bonded with Asriel. but it was also a month later that Chara would make the choice that would change everything. and i knew that if i changed that one thing, the timelines may finally be at peace. after i put in the coordinates, i pulled the lever and had the machine close around me. i was soon warped off to the time i desired. i would soon meet up with Chara and Asriel.

February 29th, 201X.

Chara POV:

I had finally made up my mind. I was tired of my family treating me like shit and hurting me both physically and psychologically. I couldn't take it anymore. I went to the edge of the nearby mountain, found a very deep crag, and I jumped, having no regrets. I was going to die alone and I would never let my family know anything. I let my body go limp as I saw I was only a few feet away from the ground... but when I fell into the ground, I was shocked when out of nowhere, something popped up that actually softened my fall... for some reason, a patch of flowers appeared as well as very soft dirt that felt almost like a cushion.

"What the... why?" I asked in utter confusion, wondering why the flowers and ground were soft enough to cushion a fall of nearly a hundred feet high... and then I heard some voices.

"Come on, I heard it over here!" said the voice of a young boy. Oh great, I thought. There are asshole humans down here too... or so I thought. When the owner of the voice came into view, he looked unlike anything I'd ever seen before. He looked very furry all over, wore a shirt of light green with a yellow stripe across the center and he was about the same height as I was. And the other thing? He was some kind of goat that was able to speak and stand on two legs, almost like a person!

"Oh, hello... you've fallen down, haven't you?" the kid asked, me looking at him in surprise before I tried getting up, me groaning at how, despite the cushioned fall, I still felt a bit of pain. "Here, do you need help?" the young kid asked, me being hesitant until I saw his look. He was looking at me with... genuine kindness... I finally smiled and accepted his offer, the kid helping me off the ground after.

"So... what's your name and what are you?... I'm uh... I'm Chara..." I said, a bit bashful for some reason.

"Chara? That's a nice name! My name is Asriel... and, well, I'm a monster," he said, me being surprised at that.

"Monster? But... weren't monsters completely eradicated centuries ago?" I asked in confusion.

"Is that what the humans teach at your schools?" Asriel asked with surprise.

"Well... not at schools, but just by word of mouth... something about a big war happening because of evil monsters or something and that humanity barely escaped extinction afterwards," I sighed.

"That's the complete opposite of what really happened... it could barely be even called a fair war, or even war in general. My dad and mom have records of the war that happened and how it was caused because humans feared monsters, mainly because of our abilities of magic and absorbing human souls..." Asriel said, me being even more confused by that.

"Absorbing human souls? Magic? They didn't teach that around the neighborhood..." I frowned.

"Well, the humans, with their combined might and their more powerful souls, completely defeated us without issue. In the end, only one human was killed in that battle. And when it ended, the humans had 7 different mages, all of whom absorbed a monster soul themselves by killing them, and created a barrier around Mount Ebott, where we are right now. Now, nothing can escape this place. The only thing that can, according to mom and dad, is a human or monster that has absorbed the soul of the opposite species. Such as a human taking a monster's soul or vice-versa," Asriel said, me frowning at that.

"Yet another reason for me to hate my life..." I sighed angrily, Asriel frowning at me.

"Hey, come on, don't say that. Life is always worth living," Asriel said with a kind smile, me frowning and shaking a bit.

"Listen... Asriel... you don't know what I went through on the surface... my folks... my family... they were terrible people... they hurt me, they broke me, they made me feel like garbage every day... I tried to jump off that cliff to kill myself, not be saved by falling on magic flowers," I said as I shuddered with anticipation and anger. I wanted to die, but now I was simply trapped in a place I'd never be able to escape from.

"Chara?" Asriel said as he took me and wrapped his arms around me. At first, I struggled a bit, expecting him to try to strangle me... but only then did I notice that he wasn't harming me. He was hugging me. "You're right, I don't know what you went through... but I want to try to help you out," he said with a smile, me sighing and falling to my knees from the warmth of his hug. "How about you come live with my family? We'd treat you much better than whoever you had before," he said, me looking at him with a small smile, just from his face. It was so innocent and pure... how could I say no to that kind of face?

"Haha... ya big dork... okay, I'll give it a shot," I smiled with tears in my eyes as Asriel then smiled widely and hugged me again before he let go and motioned me along. "Come on, it's gonna be a bit of a trip to get to the castle," he said, me being surprised, but I walked along anyways. Castle? Either he was bluffing, or this kid was a monster child of royalty! I had to wonder what I'd do if I were thrust into a life like that... it'd certainly be better than my life on the surface, especially since I couldn't stand that life... and if I stayed down here, then I may be able to finally escape. To never have to deal with my horrible family ever again... I really hoped this would be the life I deserved.