Wataru Takagi is a police sergeant and detective in the Tokyo Metropolitan Police Department's First Division, actively involved in criminal investigations. His character design evolved over time, transitioning from spikier fringe hair and a darker skin tone in earlier appearances. He partners professionally with fellow detective Miwako Sato, with whom he shares a developing romance spanning the Conan Arc, Sherry Arc, Vermouth Arc, Boss' Cell Phone Number Arc, Kir Arc, Bourbon Arc, and Rum Arc. His casework frequently involves collaboration with Inspector Juzo Megure and Detective Kazunobu Chiba. Takagi participates in investigations and operations across non-canonical films, OVAs, and specials. He drives a silver Nissan Skyline ER34, is right-handed, and prefers dogs. Within the television special Episode One: The Great Detective Turned Small, a retelling of the series' beginning, Takagi makes a cameo appearance, demonstrating his established position in the revised narrative timeline.