Suprised, scared, and mischievous

You a master assassin find yourself alone in Japan after your parents leave to work in America. You hear about a mysterious octopus who is said to have destroyed the moon and has a bounty of 10B yen. You of COURSE want to get your hands on it! However, rumor has it that the octopus you seek has rolled in as the new home room teacher, at Kunugigaoka Academy. So your boss enrolled you there since you just so happen to be to going into Junior High and well you're an assassin! However on one of you Assassination jobs, someone appears to have seen you commit your crime. And that person, Akabane Karma just so happens to be in E- class with you.
THIS IS MY FIRST BLANK X READER FAN FIC SO PLEASE DO NOT JUDGE IF HORRIBLY BAD!