Devourer of Anomalies

In the heart of 404's headquarters, a black humanoid figure adorned with striking green outlines materialized. A conspicuous cavity adorned its chest, housing a sphere with two encircling rings. The entity's head bore an indescribable "shape", reminiscent of a singularity voraciously pulling everything around it.

As 404 entered the HQ, he laid eyes on the enigmatic figure, seemingly oblivious to his presence. Without warning, the entity morphed into a form resembling 404 — donning a trench coat in a matching color palette, a sweater, pants, and slippers, maintaining a skeletal structure.

With cautious steps, 404 attempted to conceal his presence within the mainframe. Yet, as he drew closer, the entity, without acknowledging him, abruptly struck him in the face and propelled him backward with an unseen force of telekinesis.

"I thought you'd be much tougher, HE really kept his promise," said the entity. 404 remained motionless, observing as the entity settled into a seated position on a floating black block.

"You seem confused. I thought you heard about me from the other errors or viruses," said the entity.

"What do you mean?" 404 asked, his tone growing even more confused.

"Oh, I forgot. I killed Error while you were way too busy with HIM in the Transvoid," the entity said and then chuckled. Even with his mask on, 404's face betrayed his emotions — his anger was escalating, yet he maintained a facade of indifference.

"So, what are you ?" 404 asked.

"I thought you saw Error like a son. I was wrong. Anyways, they call me Avast," said Avast, who then teleported behind 404 and gave him a push. Suddenly, a hole opened in the ground, and 404 tumbled into it. The descent felt endless until he finally crashed onto the floor. As he stood up, 404 found himself in an endless corridor with doors lining each side.

"Interesting. However, I can't get out of here," said 404 to himself. He attempted to teleport and warp reality, but it had no effect on the realm.

"HE really knows how to negate the mainframe, I guess," said a bodyless voice. 404 ignored it and began walking in the endless corridor, entering doors only to find himself in the same place again and again. Opening one door, he stepped into a realm devoid of gravity — an endless cosmos with cosmic bodies that remained out of his reach. Suddenly, a white floor materialized beneath him, and Avast appeared.

"Did you like my maze ?" asked Avast in a sarcastic tone.

"I hated it" said 404.

"Too bad you will hate this more—" Before Avast could finish, 404 charged at him. Avast dodged the attack and delivered a swift kick from behind. 404 tumbled to the ground, only to be impaled by a spike emerging from his chest.

"I don't know why people see you as some devil or all-mighty being ; you have no power or such, like your hand-to-hand combat," Avast said. 404 teleported behind him and attempted to punch him, but Avast dodged it, swiftly grabbing 404's arm and slamming him to the ground.

"You got your teleportation back ? Cool. Also, are you made out of matter?" said Avast, laughing as he then snapped his fingers. 404 dissolved into quarks, and even those quarks got destroyed. He reappeared and charged at Avast again.

"You don't learn, do you ?" asked Avast. He attempted to manipulate the quarks in 404's body, but it didn't work. 404 retaliated by punching Avast in the face, sending him flying.

"That hurts, I must admit." Avast stood up and fired a blast made of anti-matter, completely destroying 404's body once again. 404 reappeared, this time able to use his abilities. He summoned Blasters, but Avast dodged them all at once. Then 404 summoned orbs that shot God-Rays with speeds never seen before.

"Oh you improved them ?" asked Avast who then dodged the God-Rays.

"I have better stuff," said Avast. He then fired green lightning from his fingers, faster than the God-Rays. 404 couldn't dodge them and fell to the ground.

"Don't you like talking whilst fighting ?" asked Avast, continuing to electrocute 404 with the green lightning. Suddenly, 404's mask broke, and everything came to a halt. Avast could still see, but he couldn't move. 404's hands and body started to get covered in a black and blue substance.

"Unlike William, I'm not limited to the Mainframe." 404 raised his hand, and with a bright light, Avast was knocked out. 404 found himself back at the headquarters. However, William regained control for a few seconds, created another mask, and wore it.

"That was close," said 404 to himself. He began researching Avast, starting with the Multiverses Mecha404 collected. His aim was to communicate with glitches and Errors from those Multiverses. However, to his surprise, he couldn't find anyone, not even those associated with glitches. Undeterred, 404 expanded his search to Multiverses outside of Mecha404's collection. He visited four Multiverses ; the first three had no glitches or Errors, but the fourth had an anomaly in spacetime — an Undyne. She shared valuable information about Avast. Interestingly, in this Multiverse, Avast appeared in a different form — an entity that eradicated errors, glitches, and viruses.

Armed with this new knowledge, 404 teleported back to his headquarters and encountered Jack.

"You know, this Avast guy is a pain in the ass," said Jack.

"What do you want ?" asked 404 in an annoyed tone.

"I'm here to give you an offer : we work together until that thing dies," said Jack. Despite his uncertainty, 404 agreed.

"Sure," said 404. Avast, observing them from his pocket dimension, took note.

"It's interesting that an error and a virus work together," Avast remarked to himself. He then ceased watching them, appearing in a different part of his realm.

"I sometimes wonder why Sanses become errors more often," mused Avast, looking at the chained humanoid entity. With a gesture, Avast broke the entity's neck, only to fix it and subject him to the highest degree of pain possible through his powers. Then, he created a zero-dimensional cage.

"This should be enough," said Avast. He then manipulated the dimensional aspects of the entity, confining him to negative dimensionality, and imposed madness upon him. Avast concluded by teleporting the entity inside the zero-dimensional cage he had crafted. Wandering within his pocket dimension, Avast visited various layers of it.

"This is straight up stolen from the Backrooms," said Avast, observing the endless maze with yellow wallpapers, carpet, and buzzing fluorescent lights.

"There is something missing... hmmm," Avast continued talking to himself.

"Oh, I remember now, this place needs to make people become mad, even madder than it can already," said Avast, who then snapped his fingers, causing the place to force madness onto everyone who enters. Avast proceeded to confront both Jack and 404, appearing behind them. Though both Jack and 404 sensed him, they acted as if they hadn't noticed.

"I know you noticed me, so there is no point in acting," said Avast. Jack and 404 turned to face him. 404 charged at Avast, who stepped aside and delivered a kick to his stomach, sending him flying. Jack summoned chains that wrapped around Avast's arms, but the chains fell to the ground as Avast walked straight through them. Avast then froze Jack in a temperature lower than absolute zero. As 404 stood up, he summoned orbs that shot God-Rays. Avast skillfully dodged all of them.

"Didn't you learn your lesson?" asked Avast as a void expanded inside 404's body, erasing him from existence.

"Now you and I are the only ones left, Jack," said Avast as Jack adapted to that temperature.

"Heh, that won't work on me anymore," said Jack as a red forcefield surrounded Avast.

"Huh?" said Avast as the forcefield exploded. Avast was on the ground, and then someone picked him up.

"You know, erasing me from existence is not enough," said 404, punching through Avast and creating a hole. He then summoned Blasters that exploded, causing Avast to regenerate his body. Avast summoned clones with the same power as the original, and they speedblitzed 404 and Jack. 404 kicked one of the clones and summoned cubes that were going to explode upon contact, but the clone dissolved them into quarks.

"You freaks also have that?" said 404 with an angry and confused voice. He summoned orbs that fired God-Rays, hitting the clone and erasing it from existence.

"Thank God they are slower than the original," said 404. Avast then appeared behind him, but 404 turned with surprising speed, shooting a God-Ray that had no effect on Avast. Avast retaliated by punching 404 in the face, sending him flying. Meanwhile, Jack managed to defeat the clone attacking him.

"Well, you see, I need to go now. I need to talk to somebody that William might know," said Avast, laughing as he left Jack and 404 alone.