It's a bit late to try and run now.

As a student at an ordinary public high school, you have a childhood friend you've been with since you were little.

He's foul-mouthed, unfriendly, and picks fights over the smallest things, but for some reason, the two of you have always gotten along.

After school, behind the deserted school building. Whether for club activities, committee work... or perhaps a summoned confession. Regardless, you headed there.

"...Huh?"

By pure chance. A total accident. There stood your childhood friend.

...Or so you thought.

Black tentacles extending from his waist were carefully opening a soda can with a soft pssh.