Reader's P.O.V

I shuffled my way through the snow the wind cutting through my (f/c) jacket. If only I hadn't been so curious as to explore the mountain near my home, Mt. Ebott. I soon came across what looked like a bridge. I would have crossed but a gate as tall as me prevented it. When I decided I should try to slip through, I heard a deep voice behind me.
"H U M A N, D O N T  Y O U  K N O W  H O W  T O  G R E E T  A  N E W    F R I E N D? T U R N  A R O U N D  A N D  S H A K E  M Y  H A N D."
I warily turned around and shook the person's hand to hear a whoopie cushion going off. I gave a little snort of laughter, along with the voice. When we finally ceased our laughter, the voice introduced himself.
"Sans, Sans the skeleton. What's your name kiddo?" "(Y/n), nice to meet you Sans." He smiled and said "Listen kiddo I'm supposed to be on the lookout for humans, but I'm way to lazy. Now my brother, Papyrus, he's a human hunting fanatic." "Great." I say sarcastically. Sans smiles and adds "But he wants nothing more then to be in the Royal Guard, think you could make his day?" I thought about it for a moment before nodding. I followed Sans through the bridge and we came to a clearing before Sans told me that his bro was coming and no matter what he said he wouldn't hurt a fly. When I first saw Sans, a real walking talking skeleton, I was frozen but now? A very tall skeleton stood before me.

---Time Skip to when the barrier is broken, ya big time skip---

I stood with the monsters at my side, we had just gotten here. Flowey, who accepted he needed to stop being so grumpy.
Toriel, who was a mother figure.
Sans, the punny skeleton.
Papyrus, who was too kind for his own good.
Undyne, who would do anything for her friends.
Alphys, who's an amazing friend and fellow anime lover.
Mettaton.... who's a little difficult to like, but still a good friend.
And King Asgore, who would be a noble ally and kind-hearted friend. The sunrise in front of us was spectacular. Staying down in the underground a few weeks really got to me, how the monsters stayed under for so long made my soul hurt a little. The others started to head down into town where your house was, along with your parents (and siblings if you have any). I smiled a bit, happy my new friends could see the sun. I watched the sun rise until I felt a hand on my shoulder. Turning, I saw Sans.
"Oh, hey Sans what's up?"
"I just wanted to thank you."
"Thank me?"
"For breaking the barrier. Thanks, it... means alot."
"Of course!" I said with a smile. "I can't stand being stuck somewhere so I felt really bad for you guys." He nodded and watched the sun with me for a moment, the stars sparking brighter then before I fell. "You've seen the echo flower field right?" He asked suddenly. I nodded slightly puzzled where this was going. "And you know the crystals on the ceiling that look like stars?" I nodded again. He sighed and turned to me.
"I remember my bro and I were there once and he had said 'Sans, do you ever think I'll be able to see the real stars... on the surface one day? And the sun, the clouds, the moon? Or even just the sky?' I said yes knowing that well, we would be able to when just one more human fell down. And now thanks to you my little brother's wish came true. So thanks for that." I gave him a smile and hugged him. When I felt him hugging back I said again "Of course." We turned and watched the sunrise a little long before Sans turned to me again. "(Y/n), it really makes me happy that my brother and my friends get to see the surface. And knowing that a beautiful girl such as yourself did it, just for us." I blushed slightly at him 'beautiful'.
"What I'm trying to say is, I love you, (Y/n). You saved us, you gave me hope to see the surface, for my brother and friends to see the surface. And... you gave me the chance to love again. Cause kiddo, some time before you fell, another kiddo did, by the name of Frisk. And, I thought I loved her, until someone by the name of Chara came and made her kill everyone. A reset came (you already know what a reset is in the story) and it kept happening, I vowed to never love again, until you came." I smiled so widely my mouth hurt. "Sans, I love you too." I hugged him even tighter and gave him a kiss on the cheekbone. He blushed a small shade of blue, then said "you missed." He pulled your head closer and your lips kissed where his lips would be. You never loved someone so much execpt for your own family.

---Time Skip, a year has passed---

(Author's P.O.V)
A year. A year since the barrier was broken. Six months since rights had changed to make monsters a part of humanity. Two months since Sans and the person known as (Y/n) got married. A month and a half since the SOULS had bodies thanks to Doctor Alphys.
Chara had changed her ways and lived with you all.
Frisk still had small feelings for Sans but soon found someone else she loved by the name of Ace.
Flowey was no longer a flower but Prince Asriel, son of Asgore and Toriel.
And Gaster was brought back from the void. You were all one big happy family, your blood family, and your friend family. But.... not all good things last forever.

But in this case.... I'll make an exeption.