Jose Martinez is a significant supporting character in the anime Hakata Tonkotsu Ramens, known for operating as a professional torturer while also being a member of the local baseball team, the Hakata Tonkotsu Ramens. His background is marked by a dramatic shift from a hopeful beginning to a life in the underworld. Originally named Alejandro Rodrigez, he was raised in poverty in the Dominican Republic with a passionate dream of becoming a major league baseball player to support his family. After failing to compete at a baseball academy, he turned to a life of crime. This path led him to a major drug cartel in Venezuela, where he became the right-hand man to the leader, Ramiro Sanchez, and was trained as the group's torturer. His eventual departure was triggered by an order to wipe out an entire family, which reminded him of his own loved ones. He fled the cartel after secretly freeing an American spy he was supposed to kill, ultimately settling in Japan and adopting the name Jose Martinez.

Despite his gruesome profession, Martinez has a personality that is notably kindhearted and sincere. He is described as having a level head and a much more grounded moral compass compared to his associates in the underground business. He deeply despises the acts of hurting and killing, viewing torture merely as a job that must be done to particularly deserving targets, such as murderers and animal abusers. He is approachable, supportive, and often offers advice to his friends. He is openly gay, an avid reader of love novels, and has stated a preference for younger, naive men, while expressing extreme disgust toward pedophiles.

His primary motivation throughout the story is largely linked to his personal connections and his desire for a stable, if unconventional, life. He finds a sense of belonging with the Hakata Tonkotsu Ramens baseball team, and his actions are frequently driven by loyalty to his friends, such as taking on jobs for Jiro or helping the hacker Enokida. His past as a failed baseball player fuels his current passion for the sport, and he even becomes a baseball instructor to Enokida as part of a debt.

In the story, Martinez serves as a reliable and powerful asset to the other main characters, often providing his unique skill set for "avenger" jobs. He works closely alongside Jiro, taking on torture assignments that Jiro cannot or will not do. His most significant relationship is with Enokida, a brilliant hacker. The two met when Martinez was hired to torture a young, unnamed hacker. Instead of harming the boy, Martinez helped him escape after learning his employer planned to frame him. Martinez gave the boy the name Enokida, and from that point on, they became close friends and partners, with Martinez fulfilling his promise to become Enokida's baseball instructor.

Martinez undergoes subtle but meaningful development, primarily in his transition from a lone operative to an integrated member of a community. His background is one of survival and flight, having left his family and later a powerful cartel. In Hakata, he builds genuine bonds, showing concern for his teammates' coordination on the baseball field and celebrating personal milestones with them, like covering a dinner bill to celebrate Enokida reconciling with his father. His journey illustrates a search for a place to belong, finding it not in the baseball stardom he once sought, but among a group of assassins and outlaws.

His most notable ability is his expertise as a torturer, a skillset taught to him by a drug lord in Venezuela. He is highly professional and can extract information using any means necessary. Complementing this is his immense physical strength, fitting his description as a muscular man nearly two meters tall. This strength makes him a formidable fighter and a valuable power hitter for his baseball team, the Ramens. He also possesses a pragmatic and calm intelligence, allowing him to think quickly in dangerous situations to save himself and others, as demonstrated when he faked an assassination to rescue Lin.