The producer explained that the original story takes on a different approach from most detective stories where the detective uses his flaws to solve the cases. In addition, he revealed that Kohinata was offered the role because he had talked passionately about his pet shrimp and killifish to his co-stars on the filming set before so he was deemed to be a perfect fit for this eccentric character. Kohinata commented that he had played police detectives before in 2-hour drama SPs but this was the first time he played someone who had problems interacting with other people. However, Hyakuno's character traits were described in great detail in the script so it helped him in the portrayal of his character although he had to grapple with a huge amount of lines. Coupled with the fact that he had just finished a stage play at the time of the filming, he was filled with fatigue both physically and mentally so he was glad to be able to complete this challenge at the end.
As Hyakuno has a great memory and remembered a traumatic incident when he was in primary school so well, Kohinata revealed that he had an equally traumatic incident back in the summer of his first year in senior high school. He was rejected by a girl who he had confessed his feelings to and left school early that day due to the shock. On his way home, he found that a puppy was following him. Although he wanted to raise the puppy, his father did not allow it so Kohinata had always wondered what was the meaning of him meeting that puppy at a time when he was feeling so down.