TV-Series
Description
Hachi Fuuma hails from the ninja village of Fuma, the eighth child among ten siblings. Despite attending ninja school and graduating, he was labeled incompetent by peers, earning the notorious title "the biggest ninja failure that comes once in a decade." He maintained a friendship with Hyakkimaru Koga, a prodigy from the Koga district.

His path shifted during a mission to recover his village's stolen Dragon Gem from Mr. Kaneari's mansion. There, he crossed paths with the phantom thief Joker, who was also targeting the gem. Captivated by Joker's skill, Hachi persistently begged to become his apprentice despite initial refusal. He followed Joker to the airship Sky Joker, where he demonstrated housekeeping abilities by cleaning the messy kitchen and cooking curry, ultimately convincing Joker to accept him.

Originally a clumsy crybaby plagued by low self-esteem, Hachi developed confidence and competence under Joker's guidance, a change noted by observers like Koga. He remains compassionate and responsible, frequently acting as Joker's moral compass while openly criticizing Joker's laziness or impractical schemes. His clean-freak nature drives him to maintain Sky Joker's tidiness and manage a rooftop garden for fresh produce. Though anxious in new situations and fearful of the supernatural, his loyalty runs deep, extending to taking bullets for Joker.

As a ninja, Hachi utilizes shurikens, smoke bombs, a grapple hook, and a small sword. He employs specialized tools crafted by Silver Heart: Image Gum (pink gum for transforming into seen objects/people) and Balloon Gum (green gum for aerial movement). Initially clumsy during heists, he honed his skills, learning to weaponize perceived weaknesses—like leveraging his "failure" reputation to lower enemy vigilance on a village mission. His analytical memory allows recall and application of tricks from mystery novels or Joker's techniques in crises.

Beyond thievery, Hachi excels at cooking (especially curry praised by Joker and Phoenix), ceramics, gardening, and housework. He keeps family ties, crafting a rice pot for his mother's birthday and hiding salty daifuku treats in his room (often eaten by Joker). He admires author Spadon King and idol group Shuffle Sisters, developing a crush on their eldest member, Ai—later revealed as Spade's assistant, Dark Eye.

In future timelines, Hachi becomes a full-fledged phantom thief, training Joker's son, J, as his apprentice while Joker explores space. He continues his supportive role, balancing ninja heritage with phantom thief ingenuity.