Frisk continued walking through the forest for several miles. The FUN detector kept beeping faster, indicating that Frisk was getting closer to finding Gaster. She had to stay determined. She knew that Gaster was close. She just had to keep going and stay determined.
After what seemed like an eternity, Frisk emerged from the forest and saw a very large hill. On the top of this hill was an enormous castle built with the same type of architecture that she had seen in New Home. Frisk was amazed at seeing such a structure. "I never thought I'd see a monster castle on the surface," she said. "It must have been built before the war."
"This has to be the place," Chara said as she looked at the FUN detector. "FUN readings are off the charts here."
Frisk looked around at the exterior of the castle. It was made of massive stone blocks, and was surrounded by an exterior wall. The structure was largely intact despite its extreme age, but there were large holes in some of the walls. Frisk walked through one of the holes in the exterior wall and saw that there were pieces of weapons and armor scattered all over the courtyard. Occasionally, she would also see dust blowing around. "There must have been a battle here during the war." said Frisk. "Do you know about any of the battles that took place?"
"No," answered Chara. "Mom, dad, and Asriel never said much about the war other than that it was a time of terrible fear and loathing on both sides."
"You know, the only thing I regret from my journey underground was that there was no way to save Asriel from turning back into Flowey, now that you mention Asriel," said Frisk.
"Me too, Frisk," replied Chara. "But there's nothing we can do. Let's focus on the task at hand."
Frisk entered the main keep of the castle through a wooden door. The castle was just as large on the inside as it was on the outside. Looking around, Frisk saw massive stone pillars, and corridors that seemed to go on forever. The castle also had glass windows. As Frisk walked through the corridors, a feeling of impending doom swept over the place, sending a chill up her spine. "I can't give up," Frisk thought to herself. "I've got to keep going for the sake of the whole world." After a while, Frisk came across what appeared to be the throne room. Standing in the center of it was a tall skeleton dressed in a black jacket. He had his back turned toward Frisk. "You must be Gaster." Frisk said.
"You are correct," Gaster said. "But you should not be here, human."
"What is this place?" Frisk asked.
"This castle was the site of one of the last battles of the war of humans and monsters. The humans laid siege to this place and slaughtered countless monsters, including the king who reigned during the war. When the king's son, Asgore, took the throne, his first decision as the new king was to surrender to the humans in order to save the lives of the remaining monsters. Then, the humans chose to seal our kind underground."
"Why are you invading our world?" asked Frisk. "Why are you tearing apart the space-time continuum? What happened to you was tragic, but it was no one's fault. Why destroy our world?"
"There is so much you have left to learn, Frisk." said Gaster.
"How do you know my name?" asked Frisk.
Gaster turned around, revealing that he was indeed a skeleton like Sans and Papyrus, but his eyes were misshapen and his skull was cracked. "When I was scattered across the universe, my essence was spread across all of time and space. I was able to observe everything that happened in our world and all the others, but I was unable to interact with anything. I witnessed your journey through the Underground, and I saw you destroy the barrier. I know what my old friend Sargon has sent you to do. He has deceived you. I have no intention of destroying your world, but he does. As we speak, he is following you here. I cannot allow him to capture me. Unfortunately, that also means that I must end your life. Even if I were to escape, he could find me again with his FUN detector. I have to put an end to him now, and I will be more that capable of doing so with the power of your soul. Goodbye, Frisk."
Gaster summoned a group of Gaster Blasters similar to the ones Sans had used earlier. They all started firing at Frisk, forcing her to zigzag around and hide behind pillars to avoid being blasted. "Gaster, stop attacking me!" she said. If Sargon really is up to no good, we can stop him together."
"I'm sorry human, but it's too late." Gaster said as he summoned more Gaster Blasters. Frisk ducked, jumped, and ran away from their lines of fire. "Sargon has always hated humanity for imprisoning monsterkind underground. If he manages to take me, he will steal my power and use it to exterminate humanity." He summoned more Gaster Blasters, and Frisk dodged them.
"How will he do that?" asked Frisk.
"My soul has immense power for a monster soul. As a monster, he cannot absorb a monster soul. However, he can extract its power and use it to resurrect the Father of all Monsters."
"Who?" asked Frisk.
"I've already wasted too much time talking, said Gaster. "Sargon is almost here. I have to end this now." Gaster summoned more Gaster Blasters, and Frisk could not dodge all of them this time. She took a direct hit to the abdomen and fell over, screaming in pain.
Gaster sent in one more Gaster Blaster, and it started charging its laser to finish Frisk off. "Gaster, is this really what Sans would have wanted?" Frisk asked, pleading with Gaster."
Gaster stopped charging his Gaster Blaster. "You're right, it's not. I'm sorry, human." He helped Frisk get up. "Sans could have killed you the moment you left the Ruins, but he refused to take the easy way out. I should learn from his example."
"Will you tell me more about this 'Father of all Monsters,'" Frisk asked.
"His name was Zeregoth. He was the very first monster, from whom all others are descended," Gaster replied. He can take whatever form he wishes, but usually takes the form of a dragon. However, his true form is that of a boss monster like the Dreemurrs. He lived long before the war that caused monsters to be sealed underground, and he was worshipped as a god. He was the oldest and most powerful monster ever to live. One day, however, he had a prophetic vision of the monsters being sealed underground. In an effort to prevent this, he declared war on humanity. He was defeated and cast into the void between universes, and there was a period of peace afterward. However, his followers continued to kill humans in an effort to bring their god back. Because of this, the humans declared war on monsters and sealed them underground. In the end, Zeregoth's own actions were what led to his people being sealed underground. "
"That's very sad," Frisk said.
"Yes, it is," replied Gaster. "Some monsters, like Sargon, still worship him and hope to bring him back into our world to wreak havoc on humanity. For the sake of our whole world, we cannot allow him to-"
Gaster was cut short when a magic spell hit him and caused him to fall to the floor, paralyzed. Standing behind him was none other than Sargon the Sorcerer, who was accompanied by a green humanoid reptilian monster.
"Hahahaha," he laughed wickedly. "You foolish human. You led us straight to Gaster. Now he is ours, and soon the whole world will be as well!"
"Why are you doing this?" Asked Frisk. "The war is over! The barrier is broken! There is no need for any more violence!"
"Resurrecting Zeregoth is the only way to get revenge on humanity for sealing my kind underground for countless centuries." Sargon replied. "Soon lord Zeregoth will return, and humanity will perish for what it has done to my people. We will have a new world that has been cleansed from the human scum. And it's all thanks to you, foolish human." He turned to the reptilian monster standing next to him. "Get rid of her, Alazar," he said, pointing to Frisk.
"Yes, lord Sargon," said the reptilian monster. With that, Sargon teleported away with Gaster. Alazar drew his sword and charged at Frisk.
"What have we done?" Frisk thought to herself as Alazar charged at her.
Continued in Chapter 7
