杖の男

An assassin attempting to hunt down Hitomi Osawa soon after she hands off the ransom money.

His identity is Kyozo Tateno, a detective at the Shibuya Central Police Station. Kano looks up to Tateno and has based his detective "Dick Diary" based on the various dictums Tateno provides.

Tateno is a childhood friend of Achi's parents, having been in love with Kotone even long after her death. Daisuke asked Tateno to kill Hitomi so that her heart could be transplanted into their daughter, Suzune, and save her from her terminal heart condition.