Katashi the dual identity police

This story tells the life of an 18-year-old boy named Katashi. Born at 04:00 pm with a strange diamond mark on his forehead, he enjoyed a normal childhood when he was 17 years old. He was a very sociable boy, he liked to go out to parties but when he turned 18 his birthmark disappeared, his attitude changed, he no longer spoke, it was almost strange, when he finished work at 12:40 am he left very quickly, they did not see him again. until the next work day. Some thought that this strange behavior was the result of him being a demon or a hero, but the truth is that when it was around 1:00 pm he turned into an 18-year-old girl.
named Yuzuki Takanashi, this was the cause of her sudden change
behavior, he didn't want anyone to realize the truth.