Cashman's true identity is Jiora, an alien police officer from the planet Biretijon. While pursuing dangerous criminals through space, his spacecraft suffered damage, forcing an emergency crash landing on Earth. This crash accidentally killed Chapat, a human police officer from Slope Town known for his cowardly and lazy nature.

To survive on Earth, Jiora fused with Chapat's body, adopting his physical appearance and memories. This allowed Jiora to seamlessly assume Chapat's identity, taking over his role as a Slope Town police officer and inheriting his personal relationships, including Chapat's girlfriend, Shampur. Jiora's true alien form features purple skin and bears a noticeable resemblance to Frieza's race from the Dragon Ball universe, reflecting creator Akira Toriyama's concurrent work during the Frieza Saga.

Requiring gold worth approximately 17 million yen to refuel his spaceship for a return to his home planet, Jiora found his police salary insufficient. To raise the funds, he created the alternate persona "Cashman" – a superhero who performs heroic deeds explicitly for monetary rewards. Operating in his true alien form, Cashman rescued civilians from criminals and confronted threats, including the original alien criminals responsible for his crash.

Cashman possesses notable combat abilities, including a technique named "Big Bang Attack." Despite sharing the name with a Dragon Ball technique, Cashman's version manifests as a powerful kick instead of an energy blast, capable of destroying an alien adversary's head. Maintaining his dual existence required Jiora to balance routine police duties under Chapat's identity with unpredictable Cashman operations, a situation often complicated by Shampur's expectations and the constant challenge of preserving secrecy.

Throughout his efforts, Cashman encounters repeated setbacks in accumulating the necessary funds; new obstacles consistently arise whenever he approaches his financial goal, forming a persistent cycle central to his character development.