Ryu Katsunaga

About

He is 24 years old.
Oto police department, public safety division.
Kota's classmate and roommate in the police academy, one of Kota's few friends.
He was transferred to the oto department in October
He has two younger sisters (the older one is a highly knowledgeable college student. The younger one is a total ditz.
His sisters call him Ryu-chan.