Note: This story is inspired by TheagentKevinlee and his fanfiction"2021 Yandere Halloween Special".

The start of the story.

When Theodor Brunner was sleeping in his room, he suddenly found himself in a different place now.

Brunner: *Wakes up* Augh...Where am I?

He started to look around the surroundings and realized he is in the mysterious place with a few lights. Strangely, the wall has codes moving vertically on it which look likes something came out from The Matrix.

Brunner: Mein Gott. What is this place?

???: Hey, you. You're finally awake.

Brunner looked back at the source of sound and saw a man in suit.

Brunner: G-Man?!

???: Oh sorry. But I'm not G-Man.

Brunner: Then who are you?

???: I'm the Overseer, who responsible for maintaining the order of the universe. You can call me Mr. Overseer.

Brunner: Nice to meet you. Mr. Overseer.

Overseer: And what's your name?

Brunner: Name's Theodor Brunner.

Overseer: Nice to meet you as well. Mr. Brunner. Welcome here.

Brunner: *Laugh* Honestly. I thought you are G-Man for a second.

Overseer: *Laugh* Oh really? Mr. Brunner. Back to the topic, do you know why are you here?

Brunner: I don't know sir.

Overseer: Because I send you here for a important reason Mr. Brunner.

Brunner: Then what reason you send me here for?

Overseer: Before I say about it, do you know what is yandere?

When hearing that y-word, Brunner started to become very serious.

Brunner: Isn't that a crazy psychopath girl who wants love from their partner with extreme measures?

Overseer: Very well. It's seems to you are aware what yandere is. The reason I send you here is stop yanderes from successfully accomplished their evil plans.

Brunner: What exactly is their evil plans?

Overseer: Well you see Mr. Brunner. The yanderes are planning to invade Earth by travelling through a dimension which connected to somewhere around the Earth. So they can take the male population in Earth.

Brunner: *Sweats nervously*

Brunner mind's: For God's sake. Are those crazy yanderes trying to expanding their Lebensraum?

Overseer: Don't worry. You will be started with Charon's yanderes. As the first of the yandere genres.

Brunner: Charon's yanderes?

Overseer: Not popular in your country's anime community? I know, but... They're more willing to have you for themselves. There are others... from different genres.

Brunner: I see Mr. Overseer. What could possibly go wrong? That is?

Overseer: Azur Lane,Honkai Impact, Arknights, Girls Frontline, Counter Side, Kantai Collection and a special guest... which is Komeiji Koishi's Heart Throbbing Adventure!

Brunner: *Sweats even more nervously*

Brunner's mind: Oh God. Please don't tell me that I'm going to die as a disgrace of my family, Gott and Vaterland.

Overseer: Oh, just relax Mr. Brunner. Of course you will be lock and loaded... only with a few conditions.

Brunner: Danke schön... What is the condition Mr. Overseer?

The Overseer summoned a weapon crate through a portal in front of him.

Brunner: Holy...

Overseer: Here's a few conditions. Number one, you can only use weapons and attachment from early World War One.

Number two, your armor will be only the German M15 tunic and trousers reinforced with steel body plate. You will be also equipped with
M1895 Tornister, M1916 Breadbag and a camouflaged Pickelhaube. So stay hidden, soldier.

Number three, two winning conditions. Kill all of the yanderes or escape unharmed. Although, you will have more favors if you kill them.

Number four, you have only one chance. If you failed the mission, you will be enslaved by yanderes for eternity.

Brunner choked by his own saliva and coughed.

Brunner: Fine Mr. Overseer. I will stop those crazy women's plot for once.

Overseer: Good luck Mr. Brunner. I hope your greatest strength and wits from Fallschirmjäger will help in your survival.

Brunner looked inside the weapon crate which is glowing inside.

Brunner: Let me see... What should I choose for my weapons...

Weapons for Theodor Brunner:
- Gewehr 98 (With scope and bayonet)
- Mauser C96
- Field Shovel