Jinkurō Isarizawa is a supporting character in the anime Revenger, known for his role as a clever and morally ambiguous official within the Nagasaki Magistrate's Office. He holds a position as a yoriki, a police official of the shogunate's security apparatus, where he has built a reputation for taking credit in cracking down on opium trafficking. However, this official duty contrasts sharply with his personal life. He is deeply entrenched in the city's pleasure districts and is known by the nickname Kaimaki Yoriki, which references his habit of frequenting brothels and surrounding himself with many prostitutes. Despite this frivolous and somewhat sleazy exterior, he is in fact a very shrewd, calculating, and manipulative individual who is deeply connected to the town's underworld.

Physically, Jinkurō is recognized by his burgundy-colored hair worn at neck length and his purple eyes. He often appears with stubble, and a notable feature is that one of his eyes is typically showing, contributing to his laid-back yet observant appearance. His charismatic and carefree demeanor allows him to navigate the complex social dynamics of Nagasaki with ease. He leverages his relationships, particularly with the courtesans and managers of the entertainment quarters, not just for leisure but as a means to gather valuable information. This network of spies and informants provides him with gossip, rumors, and concrete intelligence, making him a master of secrets and a key player in the city's hidden power struggles.

Jinkurō's primary motivation appears to be self-serving, using his various connections and his position for his own ends. He is willing to use anyone, including the Revengers, to achieve his goals. Despite this, his role in the story is crucial as an informant. He is not a frontline fighter but rather a strategic partner who provides vital intelligence to Yuen Usui, the leader of the Revengers. His information, ranging from the movements of rival clans to shifting alliances among the criminal elite, is critical for the Revengers as they navigate the complexities of the underworld to carry out their revenge assignments. While he often mocks Yuen's serious nature, their relationship is built on pragmatic trust and a long-standing familiarity, with Jinkurō offering consistent support from the shadows.

In his relationships, Jinkurō maintains a neutral but beneficial stance towards the Revenger group, assisting them indirectly by manipulating situations or passing along intelligence without getting directly involved in violence. His deep ties to the pleasure district are mutually beneficial; his presence is tolerated as he keeps tabs on both patrons and performers, while the district serves as a source of both his personal indulgences and his professional intelligence. While he does not experience a dramatic transformation, his character serves to reveal the depth of corruption and intrigue in Nagasaki. His notable abilities are not physical combat skills but rather his intelligence, charm, information gathering, and his unparalleled ability to manipulate social dynamics to tip the balance of power between various factions for his own amusement or benefit.