The heroine should be at the Armed Detective Agency, and she came about half a year before Zai.
Probably Sumikaku Valley, Hakata Ramen, Italian Cowboys, Bleach Schoolboys, Yokohama Stray Dogs, Rainbow Sentai, Rabbit and Her Queen Bee, Ikebukuro Extraordinary, Shark Tennis, Black Lagoon, etc.
I will reorganize the text during the summer vacation.
Concept: The heroine should be in the Armed Detective Agency, coming about half a year before Zai, and able to compete with Chuuya in physical skills. His special ability is to control the field. He once stayed in Hakata for a while and escaped from the company. There are many friends.