Takagi has a short crop of dark hair and dark eyes. He is seen wearing a dark suit and tie.
Takagi, along with his superior, N-Suke Yamanaka, investigates Taro Kagami's school to find a connection among five students who died of heart attacks. They interrogate Miura, since he had been harassed by the bullies who died, before going to Taro Kagami's house to question him, as he had also been bullied by the students who mysteriously died of heart attacks.
When they complete their questioning, Yamanaka compares their current case to a case that occurred in the late 1970s (Takara Bank, Yamashita Branch) in which two people died of heart attacks and other "accidental" deaths occurred later.
After the five classmates of Taro's return to life, Takagi and Yamanaka return to the school to question them about the day they died. When the five students are about to answer the detectives' questions, they die again, and Yamanaka and Takagi die as well.
Later, Taro realizes it was Miura who killed them using a Death Note, and he erases their names with a Death Eraser. Taro convinces Miura to confess to the police, and they prove the notebook's effectiveness by having Miura kill Taro and bring him back to life. Yamanaka burns the notebook, but he is unaware that Taro possesses a Death Note as well.
- When asked by N-Suke Yamanaka what he would do if he had the ability to wish anyone dead, Takagi replies that he would kill all people who were not good, proving to have a mindset quite similar to that of Light Yagami. However, Takagi makes no protests when Yamanaka declares that the Death Note must be destroyed.
- It should be noted that "Takagi" is not his real name, as it is stated at the beginning of the pilot that all "victims" have had their names changed in order to protect their identities.
- “If I had that ability… …I’d kill all the people who I thought the world would be better off without. Then I’d create a world of peace with only those who had good hearts left.”