What if? (Greyster)

In the Arena

Gaster reappeared in the arena, just in time to see Toriel collapsed, sobbing on the floor. Asgore lay burnt and wounded in the center, his chest gently smoking. The demon child herself was slowly walking towards her, her hand sharpening into a scythe. As she was putting the scythe around Toriel's neck, Gaster's temper flared. An attack of integrity swooshed across the arena, the buzzsaw severing the forearm midway up. Bete Noire snarled and ran, bursting through the wall to the buildings across from the arena. Gaster helped Toriel up and turned after the demonic soul.

"Wait!" Toriel cried. "Aren't you going to help him?!" She looked awful. Her face was a mask of despair, and was streaked with tears.

Gaster jumped to the hole that Bete had made. He replied gently. "You could do more for him than I ever could." Toriel nodded at this, and a stony look of determination set on her face.

"O-Okay." She turned to Asgore and began to heal him. As she did, Gaster sped towards the building where Bete was standing. She had a smirk on her face. Gaster snapped.

Drip.

Jessica nearly died.

Drip.

Sans might still die.

Drip.

When would someone else get hurt?

Drip.

When would he not be able to save them?

His mind shattered and suddenly he was deadly calm.

•••••••••••••••••••••••••••••••••••••••••••••••••••••

Sans suddenly collapsed back at the arena. Papyrus cried out. "SANS!" His brother was sweating and clutching his chest.

No, not sweating. His skull appeared to be melting.

Papyrus felt the draining of his own soul and immediately understood what was going on. Gaster had stopped holding back. Papyrus pushed out his own soul, and Sans stopped melting.

Now it was Papyrus's turn to scream.

•••••••••••••••••••••••••••••••••••••••••••••••••••••

Gaster didn't even wait for her to attack.
Integrity attacked and sliced her arms off, the screams of surprise and fear piercing the air. She stood no chance as Gaster summoned two massive hands in midair. They grasped her and tore her in half, black blood spilling onto the top of the building. A black figure rose from her lifeless body. Gaster summoned a ginormous Blaster.

End this.

Kill them.

Fire.

As the figure turned to dust, Gaster heard Papyrus's soul scream. He snapped back into reality. He stayed conscious for just enough time to smile gently. Victory.

His vision dimmed.

•••••••••••••••••••••••••••••••••••••••••••••••••••••

Asriel, back in his normal form, leaped down form the building. Chara followed him.

"Gaster!" Asriel cried out. He knelt beside the motionless form of Gaster. Asriel checked the scientist. "He seems to be okay, just drained."

"Asriel."

"What?"

"Come look at this!" Chara's voice sounded joyfully across the roof. Asriel could tell when his brother was serious, so he went and looked. He was dumbfounded. What he saw was...

The remains of Bete Noire.

The girl- the demon, was dead. Asriel could've thrown a party right then and there, but Gaster came first.

"Chars, we have to get him to the base."