A Book Of UnderTale Oneshots But It's mostly Sans suffering

Prove To You (UnderSwap Fluff Kinda)

Summary: Alphys finally tells Sans he'll never be in the Royal Guard-a bit too harshly. Sans is heartbroken, until mysterious skeletons tries to destroy the AU. Sans manages to make his way into the Star Sanses.

~

Another normal day for Sans! He was getting ready for his daily training, ready to awaken his younger, lazier brother. Sans skipped through the kitchen. One day I'll get into the Royal Guard! Sans thought, making toast for his brother. He hummed, proud of the toast he made. Then, Sans went up to Papyrus's room, knocking. "PAPYRUS! WAKE UP! I MADE TOAST!" Sans shouted, looking at the time. he was running late! Sans ate his toast quickly, passing Papyrus. He had been working on a trick for awhile, one that would for sure get him into the Royal Guard! 

But he wasn't able to fully summon, nor control it.

No matter, he was amazing as is!

Sans ran to Alphys's house, passing the residents of Snowdin. A few whispered about him, but as usual, Sans ignored it. "Alphys! I've arrived for my training!" Sans exclaimed, standing up straight in front of Alphys. Alphys continued to sharpen her axe, ignoring Sans. "Oh! Are you getting ready? I thought I was late!" Blue added, tapping his chin. Alphys finally stopped with her axe, and sighed. She put the axe down and faced Sans. "Sans, I don't want you here. Nobody does." Alphys stated, glaring at him. Sans cocked his head in confusion.

"Sans, you're too weak. You have a single HP and don't hold much magic. You're too nice to live up to actual potential. Sans, you are never going to be in the Royal Guard-and I'm stopping our training so I can work with actual candidates." Alphys explained in her gruff harsh tone. And for the first time, Sans did something Alphys never thought he would.

Sans's forever smile faltered, his light blue pupils turning white. But he finally chuckled and said, "If that's what you want." And then Sans walked away, ducking into the shadows to teleport. Nobody knew Sans could teleport-not even Papyrus. When they saw him suddenly appear in front of his house, they were confused. But he must've just ran fast! It was already impossible for Papyrus to teleport without breaking time and space, so Sans wouldn't be able. 

Sans slowly trudged to his room, passing Papyrus's on the way. He simply sat on the bed-not wanting to do anything. A weak, 1HP monster? I'm not weak! Sans thought angrily. But maybe he was. He was never able to beat Alphys, so why bother? Sans sighed loudly and put a pillow over his face, trying not to cry. Then, his door opened. "Sans? You've been in here for, like, an hour. Are you okay?" Papyrus asked, opening his door to see his brothers face in a pillow. Sans only groaned loudly, making Papyrus glance at the sulking skeleton. "You're home early as well. Was training canceled?" Sans flinched, which didn't go unnoticed by Papyrus.

"Alright bro, what's wrong-" Papyrus stopped after seeing his brother's white pupils. In all of his life, he's only once seen Sans's eyes white and not blue. That was the time Papyrus almost got himself killed when they were still babybones. "What happened?" He asked, pulling the pillow away as Sans tried to put it back on. "I'm weak, aren't I?" Sans whispered, tears gathering in his eyes. Papyrus frowned and pulled Sans up. "No, you're not. You're one of the strongest monsters I know." Sans sighed again, looking at his wall. "It's just... I've wanted nothing more than to protect people. But apparently I'm too nice and I'm too weak!" Sans exclaimed, making Papyrus wince. Papyrus only sighed. "Well, I think you're pretty great. How about we go make some tacos?" Papyrus asked, making Sans look up. "Yeah... I suppose we could."

For the past week Sans's pupils stayed white-meaning he's still upset. Papyrus tried everything to cheer him up-but to no avail. One day, while Sans was reading, he heard screaming. Sans ran outside of his house to see people running, and 3 figures in jackets, dusting and killing monsters with... Bones? Sans immediately ran up to them. "WHO ARE YOU?! WHY ARE YOU HERE?!" Sans shouted, pulling out a few bones. Then they came out of the shadows. "Oh look, it's a little UnderSwap Sans! He's shorter than the other 2~" The one in a dusty hoodie teased. There were 3 skeletons in total-Dust, Horror, and Killer. Sans heard that the Royal Guard was coming. 

"And we're the murder trio, just to answer your question!" Killer replied, giving Sans the shivers. "Can you please leave?" Sans asked. The trio laughed at Sans, making his frown. "Ah this kid. Don't worry, we'll make your death quick kiddo!" Sans growled under his breathe. "I'm not a kid! And I'm here to protect this place!" He exclaimed angrily, ignoring the monsters that were telling him he couldn't beat them. "Oh yeah? What's a weak little UnderSwap Sans gonna do to us?" 

Weak.

He HATED that word.

"Don't. Call. Me. WEAK!" Sans shouted, dashing towards them. And without thinking, Sans summoned the hammer he had been working on-his eye glowing blue. The trio looked shocked as Sans bashed them into a building. "If that's how you wanna play!" Horror hissed, grasping his axe tighter. Sans let out a war cry, attacking the trio, dodging each attack they threw with grace, and countering the ones he couldn't dodge. Every last bit of hatred Sans held at the moment was being let out on the murder trio. He was not weak! He refused to believe it! And with every bit of determination he had in him, he summoned 2 large Gaster Blasters. "STAY THE F*CK OUT OF MY HOME YOU B!TCHES!" Sans shouted, the blasters charging, The trio were blasted, and heavily damaged. 

The groaned and got up. "I thought you said this would be easy!" Killer hissed. "Shut up! Let's just get lost. We'll bring Nightmare and Cross next time." Dust hissed. They fell through a  portal. Sans sighed, and put the giant hammer over his shoulder.

"You know what Papy? I feel much better now! How about we go make some tacos!" Sans proclaimed, turning around. What was left of Snowdin, and the entirety of the Royal Guard stared in shock at Sans. Hell, even Queen Toriel was there-watching in amazement and shock. Alphys was amazed as well. In an actual battle-Sans managed to take 3 on 1, with 1HP, and a lower LV than the trio. 

Papyrus just stared. His older brother was just as, if not more powerful than him. Sans continued to walk towards Papyrus and grabbed his hand. "Come on! Let's celebrate this victory with tacos!" Sans claimed, dragging Papyrus behind him. Everyone around stared at Sans, who was now making his hammer disappear. 

Papyrus sat on the couch, contemplating his life choices. Then, there was a knock, only 5 minutes after the battle with the 3 skeletons. Papyrus answered the door, revealing 2 different skeletons. One was wearing a yellow cape and golden crown, the other was wearing a scarf with vials, and a huge paintbrush on his back. "Hello! We'd like to see UnderSwap Sans!" The giant paintbrush skeleton asked. Papyrus stayed silent before saying, "Sans, you have some... visitors."

Sans turned off the burner and looked at the two skeletons who were just a bit taller than him. "Hi! I'm Ink, and this is Dream!" Ink greeted. "And we, are the Star Sanses!" Dream added, making them both strike a pose. Sans was silent before responding with, "I'm... Uh... Sans. But I guess you can't really call me that...?" Sans blabbered, wondering how there could be more Sanses. "Oh! We can call you Blueberry!" Dream exclaimed happily, sending a wave of positivity through the entire Underground. Ink playfully rolled his eyes and 'Blue' let them inside to talk more.

~
"You want me to what?" Blue questioned, his grip tightening on the handle of his teacup. "We want you to join our group! The Star Sanses! You can help us protect the multiverse from evil, like Nightmare's Gang! It's kind of hard with just the two of us, so we could use some help..." Ink trailed off while Dream sipped his tea. Blue put his hand on his chin, thinking it over.

Weak. I'm not weak! And I can prove it!

Blue shrugged and nodded. "Why not? I'll join your team to fight off evil!" Blue beamed, standing up. Papyrus was in the next room, listening to their conversation. Papyrus teleported to his room. Sans wasn't a child anymore-he could make his own decisions. Papyrus just hoped his brother would stay safe.