UntilTale (An Undertale AU story)

13. Tenacity.

Your POV

You walked out from the barrier melody had made, hesitantly stepping towards the gray monsters. Dangerous as it was, Cav and Mel would have died if you didn't go ahead. These monsters sure seemed a lot better than the humans on the surface, if this Gaster genuinely wanted to help them, maybe it was for the best.

You shook your head. What was that? Was that you thinking, or him? Regardless, the small humanoid one grabbed onto you, pulling you through yet another warp that made your stomach turn.

You paled. There he was, still somewhat transparent and made of smoke, but there he was. Gaster. He looked at the large glowing wall in front of you. "One down, one to go. I assume the others have ensured the royal guard will not interfere?"

"They will not." the snake monster said in a scratchy voice.

Gaster nodded, before turning to you. "And here we have Prota. That's what you go by isn't it? I truthfully don't care. You humans are barely worth speaking to, but I'll make an allowance, I suppose. Tronde, retrieve the queen." the cat monster went to the room behind you.

"Allow me to enlighten you on what is about to happen. I will absorb the souls of Frisk, and yourself. Then I will take the five human souls. The barrier will be broken, and your disgusting kind will suffer. Do not resist, I am quite capable of putting you through a lot of pain."

Tronde returned. A human woman and a goat monster walked in, magic attacks at their backs.

"Who are you? Why are you doing this?" the monster said. "Asriel Dreemurr. I was waiting to meet you. My name is Doctor Gaster." As Gaster said this, recognition passed across Frisk's face. "Gaster. Your followers told me about you. I was warned about you."

Asriel jumped forward, a magical sword appearing in his hand. Gaster barely looked at him before forcing him backward. "Don't do anything you'll regret, your highness." Gaster's voice was filled with venom. "You. You've always cared too much for these humans, those who locked our kind away all those years ago. Did they care for us? More than that, you created another hybrid, like the one who started the war. You are no king to me. You will kneel as I do what monster kind needs!"

Gaster's followers held Asriel down as gaster walked towards you. "These humans will die. Painfully now, to show you not to attempt anything against me."

Suddenly, a member of the castle guard rushed into the room, charging at Gaster. Gaster effortlessly tossed the creature into the glowing barrier behind him. A sickening hiss was heard as the monster dissolved upon contact with the wall. So much for that.

"Tronde, I thought you said all of the guards were occupied. How did one slip past?" Gaster questioned, tendrils of smoke curling threateningly around the follower.

"Because someone showed them a shortcut, G." A familiar skeleton walked into the room, one eye flickering.

"Sans. How kind of you to join us."

Sans looked around. Saying nothing, he pulled a small device from his pocket. One flick of a switch and a black portal appeared next to him. Blue magic curled around his fingertips, and a mangled white mess of a soul was pulled from it. "Here it is G. Your soul, the emotions that you threw away because you were more concerned with timelines and immortality than your own sons!" an unnatural bitterness from the skeleton made the whole room go silent. For a moment. Then Gaster laughed.

He pulled the soul towards him, cradling it in his hand. "Oh, sans. Did you really think that simply giving me a soul would make me stop? Ridiculous. I was planning to retrieve it anyways. My LV will ensure I remain committed to my goals. As for you, I'm offended. All of this is for you and Papyrus, Sans. I will make a world where monsters can live under the sky. But if you insist on fighting for the humans, I'm afraid I'll have to stop you." with that, he absorbed the soul. The Gaster that Sans had known, his father, was gone.

Sans grabbed Gaster with blue magic, but Gaster didn't budge. "I am still one with the void sans. You make such simple mistakes. Such as that human you love. They aren't even supposed to be here. They simply popped into the timeline, helped you fight someone, and you married them? Foolish, to put it gently. Perhaps I'll have the memory heads bring them here to suffer the same fate. Their soul won't break the barrier, but I'm sure Shift's soul will be of benefit." Sans' eye blazed as he desperately tried to knock him down with blue magic. Gaster chuckled drily, moving a finger and sending Sans dangerously close to the barrier. "Stay there. Now back to-"

You threw the letter opener Alphys had given you into Gaster's chest. He stumbled, pulling it out with a disdainful look. "I really did try to be hospitable, human. You're first." he raised a skeletal hand, summoning your scarlet soul. The edges immediately began to distort and pull towards the hole in the hand. Last time he attempted this, you felt sick. This time, you were in agony. You felt your body being pulled to him.

If Gaster got your soul, he'd have enough power to kill everyone in the room, if he wasn't capable of it already. You stumbled, falling to your hands and knees. The sudden movement forced Gaster's hand back, but he looked at you. You knew if he could move his face more he'd be smirking. You tried to back away. Looking around, you saw everyone else was forced against the wall, being crushed. His hand moved with you as you tried to stand up. The others were pushed harder into the rock cave wall.

You looked at him. There had to be a way out. Gaster dialed up the pain, forcing you down again. The others were loosened from the wall again as his hand was pushed back, forcing him slightly off balance. "Stop making this so difficult," Gaster demanded. That was it.

You pushed yourself forward, closer to him. The pain grew as your soul began to pull itself to pieces. "Ah, there we go. Let's make this quick." the force he was exerting on all of you blew dust and his cloak around haphazardly.

You screamed as you lunged forward. Gaster's footing slipped in the dirt as he was pushed back. The others fell to the ground as he tried to remain upright.

"Tenacity. Such an interesting soul trait. Not quite determination, not exactly bravery. But it won't save you." he pushed his hand forward, but you didn't move much. His soul flickered in his chest, leaking from where you'd thrown your knife. You stepped forward more. Loose ribbons of his cloak brushed against the barrier, crackling and disintegrating. He looked back, realizing your plan.

He growled as he tried to push you back, but you pushed against your own soul, holding yourself in place. Your soul was being mutilated by the force. You charged forward, pushing gaster into the barrier as he screamed. The sound of Gaster turning to dust filled your ears. His skull dissolved in front of you, grinning until the end. A massive wave of magic hit you, sending you back from the barrier.

The others regained their footing, looking at the pile of dust laying against the barrier. Your soul slowly pieced together as the pain subsided. Asriel cleared his throat. "That's that then." Frisk nodded.

The followers began to shake, before turning to dust.

Sans whispered. "This time, he's gone for good." You knew he had mixed feelings about that. It was his father after all. But then again, the real Gaster had died long ago. 

You'd ended something else. The story.

But is it really the end? 

Thank you all so much for enjoying the story so far! I'm going to be starting a new book of one-shots about some of the characters before we get to the next big part of the story. See you soon!

And don't worry, I'm probably going to be publishing more often, as I'm working on this for my creative writing class at school.