"I've finally found you... darling" | Disclaimer: ORIGINAL NOT BY ME, ITS A MODIFICATION

Kosaka Wakamo

Wakamo is a suspended student from Hyakkiyako Alliance Academy and one of the "Seven Prisoners" who escaped from the Federal Corrections Bureau. She is known as the "Fox of Calamity" (????) for her indiscriminate and massive acts of destruction, and her motives and purpose are a mystery. She can also be considered as a terrorist mastermind in this case. She is also rumored to be as scary as a demon with her true face hidden beneath her mask...

When she met Sensei for the first time however, she didn't attack nor point a gun at them. For some reason she got upset and ran away.

Wakamo is naturally inclined to anarchy and destruction, preferring to cause chaos and rampage wherever she goes. This got her into trouble with the police and imprisoned in the Correctional Bureau before she escaped.

After she meets Sensei however, this changes... Slightly. Though she still has a desire for violence, sadism and destruction, her feelings are tempered by her obsession and love for Sensei. Since Sensei convinced her to restrain herself, Wakamo generally tries to hold back and not cause too much trouble.
~Blue Archive Wiki

Story

Wakamo finds an abandoned fighter jet in a snowy fields, its seems to be a leftover from an unknown person out of Kivotos. Wakamo hired (not really) an unknown engineer to make the fighter jet flyble and reconstruct its controls so that Wakamo can easily get used to the jet itself.
~Self written story

Su-57's irl information

The Su-57 is a fifth-generation stealth fighter aircraft developed by Russia's Sukhoi Company. It features integrated avionics, large payload capacity, supermaneuverability,[1] and weapons systems, including air-to-air missiles, air-to-ground missiles, and guided bombs. The aircraft is designed to excel in both air-to-air and air-to-ground combat scenarios and is intended to be the cornerstone of the Russian Air Force's fighter fleet. The Su-57 has been in development since 2002 and has undergone extensive testing, with production expected to ramp up in the coming years. It is considered a symbol of the Russian Air Force and has been mostly kept secluded from battle in worry that any losses of the aircraft could damage the reputation of the Russian Air Force.
~Wikipedia