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Chapter 1: Long Ago

Many years ago, humans and monsters lived together on the surface. But then one day the humans fearful of the monster's true power of absorbing a human's soul they decided to fight back. So a war began and both sides fought hard and lost many members of their kind. But soon the humans won, having trapped the scared monster's underground, they used their magic to seal them in forever.

Some say if you climb a mount far away no one is said to return from the mount and thus no one dares to travel there.

W.D. Gaster's POV

"Gaster?! Gaster?!" Asgore called

"Coming my king" dashing towards the capital's throne room I called out. "sorry for being so late." I said out of breath.

"That is fine my old friend, listen since i have you here i got something i need to ask of you."

"of course my king, what is it that you need of me? is the core out of power?"

"no, i need you to go up to the surface and spy on some humans for me, to see if they have changed their mind sets on us."

"of course, but how? don't we need a human soul to get through?"

"i have one right here for you to use."

"oh, wow! i didn't even hear anything about a human falling down here."

"not many have, i kept it hidden, please use this soul and go see the humans."

"i will go right away." I walked away with the human soul in hand. I wandered the dark hallway towards the barrier and i was able to go through. I saw the sun light for the first time in a long time. I saw a city not far away and decided to head towards it. But soon i saw humans, in order to not make much of a fuss, I turned into a human. I walked around and chatted with humans asking each about monsters some brushed me off and others simply called them bed time stories. I soon got bored of this line of questioning and decided to try a different way. I noticed that humans loved music, I thought this would be a great way to get to know humans. But before I could do anything i was kidnapped by some lab coats. They had seen that i was a monster able to turn human.

They made me their lab rat and hurt me, i got scars on my face one going from one eye towards the top of my skull and other one from my eye on my left side connecting to my mouth. My hands they drilled through my palms and left holes on both. They let me go afterwards, i didn't hold this against all the humans. I turned myself human again filled with hope and faith that some humans can be called friends.

I met a human that proved that to me in more ways than one, his name was Paul McCartney. We bonded through music and were in a band called the Beatles together. I called my human self John Lennon. Some time had passed and it was time for me to return to new home and told Asgore of my experiences. 

But as soon as I turned back to my monster form near the opening of the underground the humans attacked me. I showed them mercy and then Paul jumped in and saved me. He died in doing so, I had lost my best friend to humans, and yet i still spared them by fleeing back into the underground. I had Paul's soul dust on me, I had to act fast. I found a soulless monster body and used Paul's soul dust to make a monster soul. But i lost a lot of his dust in the underground in various locations. But at least i had enough of him to make a new monster life. I named this skeleton monster Sans for now till I could tell if Paul had fully returned.

Once I was finished I left Sans Asleep floating in a tube to get back to Asgore and tell him of my reports. Asgore was pleased enough to allow me another visit to the surface, I did go back and married a human and had a son, but once again i left for the underground but this time i didn't return to the surface. Once I  told Asgore of my new reports I went off for the lab to see Sans. But Sans was gone, he had broken out and disappeared into the Snowdin area. I decided to let him figure himself out and live a happy life there. One of my helpers turned against me and pushed me into the Core. My data was corrupted and rewritten along with my memories I had disappeared from the timeline along with anyone's memories of me outside of Sans for unknown reasons.

San's POV

Gaster...he disappeared..on that same day a strange new skeleton came to my door in Snowdin calling me Brother calling himself Papyrus..I decided to let him in..it felt good to have some family/company till i could find out where Gaster went or how to save him.

Chapter 2: Fallen Child

"Sans!? Sans?!"

"hmm?? Oh whats up bro?"

"You know what is up brother! you haven't worked on your puzzles in eight days. I swear you get lazier and lazier everyday. What if a human comes here?! I need to capture human then Undyne will surely let me into the royal guard."

"wow, it sounds like you have been working yourself down to the bone."

"Sans!! I swear!!"

"oh come on, you are smiling."

"I know and I hate it, look i know you only have one hit point and you are easy to tire but could you please put a little more backbone into your work?"

"alright bro for you."

"thank you Sans, call me if you see anything a miss."

"will do." Papyrus walked away. I went back to my post and fell asleep.

I had a dream more like a memory..

"just one more piece there. Sans can you do something for me. If my son ever falls down here could you please watch over him for me? They are the hope of this world. The first ever known half human half monster. I know for sure he will bridge the gap between our kinds. So please for me..." Gaster pleaded to me..

I was still asleep in that tube back then but i heard everything he asked of me..yet i couldn't say anything back to him. But i swore to myself i would help, even though i didn't know what his son even looked like or his name but i promised Gaster.

I woke up cause i heard footsteps nearing my station I thought it was Papyrus coming back but boy was I wrong. I looked around and no one was visible at first then a small voice called my attention.

"Excuse me Mr. Skeleton? Have you seen my daddy?" I looked down to see a child no more than 7 years old. He looked dirty cold and scared lonely and filled with fear.

"No sorry kiddo, there hasn't been any humans down here in a long time. But i tell you what why don't i travel with you and help out."

"really?! thank you. My name is Sean, what is yours?"

"Sans, Sans the skeleton."

"nice to meet you Sans." I had a gut feeling that this was Gaster's son. I will fulfill my promise and who knows maybe Sean can help me save Gaster.

Chapter 3: Papyrus??

Sean followed me into Snowdin where I live with my brother. He seemed a bit scared, I smiled and passed the time telling him puns, puns that i once told John/Gaster. He seemed to have cheered right up. I got to my house when I saw Papyrus with Undyne i decided to teleport into the house so that way Papyrus wouldn't catch us.

I felt like he would catch us soon though so i had to think fast about my promise to Gaster about protecting this child of his. How was I suppose to do that when everyone in the underground wants to be free and here was the key..the child with a soul..Asgore would have a field day with this kid. I heard my door slowly open, "Sans? you home?"

"yeah Papyrus i am going to come down stairs right now." This sent him away.."Listen kiddo stay here no matter what. I got to smooth things over with.." I froze cause I saw the kids scare expression I turned around to see Papyrus..He wore a angry face but was too frozen in place..

"Sans..who is this?"

"now Pap..i know what this looks like just let me..explain.."

"i know him..from..somewhere.." he was glitching I had never seen this before..

"Papyrus..??" He was now speaking in wing dings..I understood what he was saying..I only knew of one monster that could speak in wing dings..Gaster..How is it that Papyrus knew Wing Dings..unless..Papyrus..was...Gaster?!!

The glitches grew worse he kept repeating "this isn't my true body..my true name is Gaster.." Sean was hiding behind me scared and so was I. I was sweating I didn't know what to do..the glitches over took Papyrus and a darkness had taken over where he stood..and then..A talk black and white figure came out of the glitches and darkness. He was as tall as my long lost friend John/Gaster. It was Gaster.

"Hello Sans it has been a long time." he finally spoke. He wasn't using Wing Dings as he knew he was around someone that didn't know wing dings. his voice deep like butter, cut through my body like a knife if I had hair it would be standing on end with excitement.

Chapter 4: W.D. Gaster

I stood there speechless I was confused, was this all a dream was Papyrus truly Gaster this whole time? I had been living with him this whole time without even knowing it.

Sean had calmed down and stepped out of my shadow , my sweating had stopped as well. The light sound of snow falling outside filled the air. I didn't know what to say to cut the tension in the room at this point. Sean had finally asked "Have you seen my daddy?"

"hmm? a human child here..wait..you aren't fully human..you are part monster.." Gaster had lit up Sean's soul studying its every detail..I hadn't heard of a half human half monster before..So did that mean I was right about Sean being Gaster's son.."I can see a powerful monster was your father as half your soul is monster soul. I am who you are seeking. I am the only monster that had seen the surface more than once and laid with a human."

"you are my daddy? but he is human..not a monster." Sean was confused.

"allow me..to show you." using magic he turned into his human form, a form I had fallen in love with in my human life. One I thought I would never see again.

"Daddy!" Sean smiled warmly and hugged his leg. John and went down to Sean's level and patted his head softly in a loving matter. He turned back into his monster form. Sean happily reunited with his dad came over to me. "I wanna set you all free. Mr. Sans can you help me?"

"sure thing kiddo and no need to call me Mr." I said Gaster looked at me. Sean yawned and went into my room. Leaving Gaster and I alone.

"You protected him?" he said in Wing Dings.

"Yes I did, I had a strange feeling that he was your son.."

"I asked you that favor when you were still asleep in the tube when I first created you from Paul's remaining soul dust..how could you have heard my plea..?"

"I don't know but I did and I remembered it even with all the resets along with you."

"I see..do you remember anything from before this?"

"yeah, I remember being human."

"really?"

"yeah it was very bonely till you." the crappy pun cheered him up and he began to laugh, a laugh that set my heat on fire and made me blush.

Chapter 5: WaterFall

The Waterfall area seemed calm and quiet as we walked along with Sean, he was cheerful and friendly with a lot of monsters. Gaster seemed proud of him, i throw some puns his way to pass time. I noticed each time he laughed hard he would glitch out a bit with it effecting pieces of the world around him. I did my best to limit my puns so as to not glitch out the world he seems to be still unstable. I am sure we would find a way to fix him.

We lost track of Sean at one point of the journey of the waterfall area, Gaster wasn't fully upset at me or at the fact he was missing from our sight.

Sean's POV

I lost daddy and Mr. Sans, i went walking it was hard for me to see in front of me due to my broken glasses. I found a small cat thing. 

"Hoi, I am Temmie." it said. I smiled softly at the Temmie. it followed me for awhile until i made my way towards a lake inside this cavern place, daddy called it Waterfall. I heard someone big metal boots stomping behind me. I turned a tall blurring shadow figure was looming above me. 

"i found you! what did you do to Papyrus?! he is never late for his reports! he has always answers his phone and for some reason he isn't now! you must be the cause you killed him!! didn't you?! I will give you justice for what you have done to my friend!!"

"But i didn't.." it didn't seem to get through to the figure it attacked me with a blue spear. "Daddy Mr Sans Help!!" i screamed out running. the flowers around me echoed my cries through the cave.

San's POV 

I heard the kid's voice over the echo flowers, he was in danger Gaster teleported us towards the screams. we found the kid he was somewhat hurt but was alright. I knew of only one person that would hurt someone that badly. Undyne was coming and we had no choice but to fight back and stand our ground against her.

"Come back here you killer!!" Undyne screamed out towards the kiddo she must have assumed Papyrus's absent was the kiddo's fault in which i mean he killed Papyrus but it wasn't true the kiddo had no Lv and Papyrus was in fact Gaster but Undyne had no way of knowing that. I dodged her spears. "You side with the human! Sans! why?! I can't let you stand!" She attacked me with full force i blocked it with a blaster.

"Come on Undyne don't be so fishy! I only trying to help you understand the situation at hand!" I didn't attack her i kept dodging i will show everyone mercy it is what Gaster had store his hopes and dreams into for.

'you are our hope' i remember the times he and i laughed at funny puns on the surface together. I didn't care that he was a monster, i knew a week before he left for the underground before i died as a human that he was a monster. I still saw him as my best friend music and bad puns brought us together. I won't let him down now! I will not break this promise not this time!

Undyne was at full force and i dodged as much as i could i was getting tired Gaster was protecting the kiddo as well. i turned to check on them it was a stupid mistake...i was hit with a spear. I could see the terror in Gaster's eyes his anger his fear..i knew he was upset.. i turned to see Undyne regretting her move..

"Hehe...hehe..i guess you can say..i am boned...hehe..hehe..well...I am..going...to...gillby's....want...any...thing....P.a.p.y.r.u.s......."

Gaster's POV

no..no....!!! NO!!!!!!!!!!! i saw Sans turn into dust right in front of me..his jacket floated softly downward toward the ground. I picked it up crying..i was glitching from being unstable. I was upset...no beyond that..i was mad.. 

"Do you...want to have a bad time!!!!" i filled with determination and anger!! I turned on my fullness of powers attacked Undyne as i did the world around us was getting darker darker yet darker..the darkness was cutting deeper..the coding of the world coming undone...the world..being deleted...I didn't care..my memories of Paul and Sans flashing in my mind..all the silly happy times..all the silly puns and music we shared..I will..not..let him die for me..again!!!

Sean's POV

"mr. sans...i am scared...daddy..he...is..truly a monster..i am scared..." i was crying i saw a button flash in front of me.. 'reset' it read. I was curious and at the same time i felt i was being eaten up by the darkness. I pressed the button..

loading from last save point..

last save point found...

Snowdin.....i was back in Snowdin.. it was back to normal.

"Brother i am home! ugh your sock is still there on the floor!!! Sans!!"

"Sorry Bro i guess i got bone tired."

"Sans!!!"

"hehe." they were back to their old selves I saved them I was okay they were okay. i was happy..but did that mean daddy didn't remember me..or his true self??

Chapter 6: The Duncle

Sans's POV

I died i know i did, the kiddo reset..I remember hearing the kid crying out for me..but i was dust.. I saw the world torn up and broken nothing but darkness and code, I hadn't seen that side of Gaster before I was shocked but at the same time worried about the kid. But in the end we started right back where we were before it all went down, the kid and I are the only ones with the memories of what had just went down.

I saw the kid crying as he hugged my leg, I patted his head told him sweet things to calm him down and told a silly pun or two. Just then that same look of fear came over his face, i turned to see Papyrus but he wasn't alone Undyne was here too. Shit just my luck two human hunters in my home and a human right behind me hiding in fear. There was no talking my way out of this one, Papyrus was glitching already and the only move I could think of at the time was short cut. I took the kids hand and Papyrus's even though he was glitching I teleported us out of the room before Undyne could even speak. 

The kid landed on me safe and sound but I didn't see Papyrus anywhere nor Gaster I looked around for him but nothing "hey kiddo why are you look at me like i got two heads or something?" This was when i noticed I was taller and I had holes in my hands just like Gaster..I walked over to near by pond and was shocked at what I saw. I had fused with Gaster I had become a Dunkle but maybe this wasn't as bad as I was thinking. I check my stats and saw we had a lot of hp attack defense so i could be more helpful to the kid against enemies that is good. Another plus was that Gaster wouldn't go all hyper cause i wouldn't die so easily, so maybe this was a good thing. We can figure out how to become unfused later, for now i was focused on our happy ending on our freedom.

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