The loud noise of glass shattering cut you off, and all voices shrieked from all around. Aether was about to draw his sword when he remembered he couldn't use his abilities in your dimension.

You

"What is..."

Slowly, Aether was backing away, the same for you. More and more students kept on appearing, running in the opposite direction that you and Aether were facing.

You

"Do you think we should go check it out?..."

Aether

"Huh?!"

Aether couldn't hear a word you said, all the noise was much too loud.

You

"I said do you think that we should check-"

You raised your voice, but the number of students running past the both of you was way too many, and you started to get separated.

You

"Aether?!"

Of course, the selfish students were only focusing on leaving the area for some unknown reason, they couldn't care less if they stepped over your dead body.

Aether

"Y/N! I'm over here!"

Aether was waving his hands all over the place, but you couldn't tell who he was because you couldn't see him through the crowd. You used some pipes to elevate yourself above everyone else, hoping to find Aether from there.

Thankfully, you spotted him in time and jumped down to go join back with him.

You

"I was asking, should we go check it out?"

Aether

"I dunno... It seems really dangerous, all those students had blood-stained clothing. Is it safe there?"

You

"Hm, probably not. Y'know, since you don't have access to your sword, I think it might just be best for us to not-"

For the millionth time, a loud sound of glass shattering interrupted your conversation. You and Aether both stared at the terrifying scene. The shattered glass was caused by a student literally eating another student. Yes, another student was devoured. The student appeared insane, with blood all over their face and bloodshot eyes. Their gut was also bleeding profusely.

Both you and Aether's eyes were widened, in pure shock. 

The student that they were literally biting out of was crying and screaming so tragically, you didn't like it one bit. 

After some time, as the student was still biting them, the student being bitten stopped their screaming, it slowly slowed down and got quieter and weaker. 

You and Aether stood there watching as the student who had been bitten simply stood up from the ground, blood pouring from their neck, and began chasing after you, Aether, and all the other students fleeing.

You were baffled; why was such activity taking place in the Upper City? Even so, if this occurred in the Underground, it still would be quite unusual. Sure, you've seen a lot of innocent people die right in front of your eyes in the Underground, but you've never seen someone bite the shit out of someone else and then get the same effects as the person who bit them.

You grabbed Aether's wrist firmly and you started dragging him right out of the school center. You were looking back and forth, extremely anxious.

You

"Aether listen. You're going to open a portal and run right back to Teyvat the moment that we leave the school grounds, alright?"

You said with a shaky voice.

Aether

"What?! I'm not leaving, I wanna help! Just give me a sword or something!"

You

"The only thing I have at the moment is blades! That'll do no good, you're not even experienced with blades!"

Aether

"It doesn't matter, I'm not leaving!" 

You

"Yes, you are leaving!"

Aether

"No, I'm-"

Another student pushed right against you and Aether's hands, separating you two once again.

You

"Hey- Aether!"

No response.

You slowed down and stopped running. 

You

"Aether!"

Once again, you heard nothing. You sighed in disillusionment, out of breath from your run. You were about to go out looking for him by climbing something so you could see from above, but you realized you didn't have much time. The anomalous humans, termed the Infected, were only a few metres away from you.

With no other option, you were forced to flee the scene without knowing where Aether was. You assumed he rushed back to Teyvat but based on his words and attitude, he may have stayed in your dimension instead.

2 WEEKS LATER

This had been going on for two weeks, and almost the entire Upper City population had been infected with whatever this was. You had no idea what was going on in the Underground because you were still trapped in the Upper City. Knowing how quickly this spreads, you'd have guessed that it's infected quite a few people in the Underground. You had killed so many of them when they attempted to harm you that it's quite depressing that they were all innocent people with no choice.

You now have a better understanding of what this particular virus was. You have no idea how it all began, but it started with a student in the school running around and biting other students with their own mouth. These students became infected with whatever that specific student had and began biting others, increasing the rate of infection.

When a person becomes infected, it's almost as if their entire mind dies. They are unable to speak or behave normally. They don't die easily either, as you discovered the hard way when you killed one because it ate your spaghetti and you literally went crazy. You've also discovered that the correct location is their neck. It is easily extinguished by striking the neck.

Your main goal was to find Aether; you were worried sick about him. You were hoping he'd found something that looked like a sword, or something that looks remarkably like a sword, and that he'd defended himself with everything he had.

You were surviving quite well, you had access to food and everything. 

While out, carefully avoiding the Infected and trying your best to not make a noise, you were searching for more food to eat.

When you heard a single pebble fall over, your attention was drawn to a specific location. You were extremely cautious, even sharply pulling out your blade, making only a subtle noise.

Yet their ears were still extremely sensitive, so of course, the Infected came running to your area. Just from a single noise that wasn't even loud.