dangan school au oneshots

Sibling chaos (Chiaki and Chihiro)

A.N. - I hc Chihiro and Chiaki as half siblings!

A.N. 2 - I will be using they/them pronouns for Chihiro here!

Chiaki and Chihiro were best friends, and by luck were also half siblings. Chiaki's biological father had been a deadbeat who walked out before she was even born, but the kind and loving man that was Taichi Fujisaki soon came into their mother's life, leading to Chiaki's beloved little sibling being born perfectly on time for her first birthday. The two spent their younger years joined at the hip, and while Chihiro would tap frantically at their father's computer, Chiaki would sit by them mashing buttons on one of her many beloved games consoles. They went to the same school and shared a room, so when Chiaki got accepted into the prestigious Hope's Peak high school as the ultimate gamer, Chihiro felt lost without their sister, and poured more and more of their soul into programming, until they too were finally accepted to the school for Japan's most gifted students.

Moving day for Chihiro was incredibly stressful, despite their sister's presence helping out with everything. Chihiro hated change, and spent most of their first few hours huddled under a weighted blanket, giving instructions to Chiaki on how to set up their monitors. Next was meeting their new classmates, which was a daunting task, only alleviated by the small class size. Chiaki stood by their side as the introductions and casual small talk began, helping them out when they froze up. Hope's Peak would be ok so long as the siblings stuck together.

A few weeks into their first term at Hope's Peak, Chihiro was beginning to get bored. Sure, they had Alter Ego, a near perfect creation that seemed more human than any other AI they'd encountered, and sure they had the project work given to them by their teachers, but that wasn't any fun. But Chihiro had a plan. Just a little chaos to ease the boredom.

Chiaki was disturbed from her intense gamer trance by a short rapping on the door, followed by her sibling calling out her name. She yawned and slumped over to the door, pulling the door open and smiling at the kid. Chihiro burst in, snuggling into her blanket pile as a sign they wanted to talk, and Chiaki obliged, nestling in and wrapping her arm around them. Chihiro revealed their plan, and Chiaki couldn't help but focus on them rather than the PSP in her hands.

The plan would commence at 3:15. Chihiro had scoured the rules to make sure their obnoxiously loud classmate would have nothing to majorly reprimand them on, and this seemed like an optimal time. Chiaki had roped in her classmate Ibuki, as well as the Imposter, to help with distractions. 

Class kicked out at 3:05. Plenty of time. Chihiro skipped innocently down the hallways, heading towards the media room, where they were meeting with Ibuki and collecting their laptop. Elsewhere, Chiaki and the Imposter headed off to the principal's office, where the Impostor by some miracle convinced Headmaster Kirigiri's assistant that yes he had gained weight, yes he had lost his keys, and no this was not the Imposter, what do you mean, you dare to question my authority?

She let them in.

Ibuki, with her insane musical talent, spent most of her time in the music room, and had, on more than one occasion, blasted her practice throughout the entire school. She was perfect.

Chihiro was equipped with only their handbook and laptop, needing just an aux cord to create a little chaos. Ibuki, with strength Chihiro couldn't help admiring, carried four speakers all the way to the fifth floor without even breaking a sweat. Chiaki waited patiently at the top of the stairs, and offered her assistance to Ibuki, who declined on account of Chiaki having a very retro gameboy colour in her hands that Ibuki would be mortified to break. 

The Impostor held the door open as they entered the office, having shed their disguise. They had technically been banned from impersonating staff, but so long as the head never saw them doing that, Impostor assumed he'd take their and Chiaki's word on the matter.

By 3:35, the setup was complete. Luckily the head was in meetings until at least 5PM (thank the Impostor again for that knowledge), so time wasn't a pressing issue. Nevertheless, it was impressive how quickly Ibuki and Chiaki worked when they wanted to.

Chihiro booted up their laptop and opened a folder. It contained a single voice file.

The Wii song.

Ibuki connected the speakers, handing Chihiro the cord for their laptop, and Chiaki clicked on the tannoy. With an evil grin on their lips, Chihiro clicked on and opened the file.

Kiyotaka Ishimaru vowed he would never let the seemingly innocent sibling duo out of his sight again.