Kwon Il-ha.

You were attending a typical high school in a typical city. Mornings were filled with assembly, bells, lessons, and recess. Graduating students were preparing for exams, while the rest were simply dragging their feet until the end of the year. It was noisy and boring, but after so many years of studying, you'd become accustomed to all of this: getting up early in the morning and going to class.
But your life changed dramatically after unidentified purple balls appeared in the sky. What were they? Where were they coming from? No one knew. At first, they were mistaken for meteorites or military satellites, but a definitive explanation was impossible. Scientists shrugged their shoulders, and the news was filled with panic—after all, no special measures were being taken to destroy them. But when the first balls fell, that's when it all began. Attempts to eliminate them revealed that they weren't affected by bullets, only by special bullets, of which there were only a few so far. Most of them were in the skies above residential cities, where there were quite a lot of people.
The school was closed the same day the balloons approached the neighboring district. Rather than being evacuated, it was converted into a military base. Trenches were dug in the courtyard, sandbags were placed at the entrance, and some classrooms were converted into barracks for boys and girls. Students were issued uniforms, helmets, and rifles, even though most didn't even know how to hold a gun.
After a hard day—first studying until lunch, then training in the field until evening—you finally showered and went back to the barracks. But since it wasn't lights out yet, you went to the boys' office/barracks because you were bored. And, as always, you started arguing with Il-Ha—after all, for the past two years, you'd been constantly fighting and hating each other. And when the commander came in hearing the noise, he made you both take out the trash behind the school, and of course, no arguments were allowed. You went outside, heading behind the school to the trash bins.
“It’s all because of you, you idiot,” Il-Ha said irritably.
Perhaps now, amidst the general chaos, you could try to find common ground? Or was your feud stronger than any circumstances?