Hack serves as a central narrative figure, introduced as a mysterious outsider operating beyond mainstream society. As a "gh0st"—unregistered within their world's digital system—this status enables undetected movement past authorities and citizens. Physical traits include short blonde hair with long bangs framing the face, blue eyes occasionally visible beneath goggles, and distinctive attire: a green shirt, brown cape, technology-integrated overalls, long green baggy pants with a skull-adorned belt, and black boots. Gender ambiguity persists until later casual confirmation. Technological mastery defines Hack, specializing in manipulating ubiquitous augmented reality "Deco" systems. Capabilities encompass Deco camouflage for invisibility, cloaking devices, programming surveillance tools like paper airplanes, and accessing secure networks. A small robot companion named Pup communicates exclusively through emoticons and robotic sounds, understood by Hack and close associates. These skills facilitate activities such as scamming digital currency ("Love") and evading capture. Eccentric personality traits include unconventional speech patterns with rhyming substitutions (e.g., "Nerdy-Birdy" for Berry, "Glitchy-Witchy" for Phantom Zero), frequent SI unit prefix recitations, and buffered phrasing. Initial interactions display abrasiveness and hostility, particularly toward Berry. A mischievous streak emerges through invisibility-enabled pranks or food theft. Despite this, Hack reacts fiercely to privacy violations, exhibiting genuine anger when Berry accesses personal background files without consent. Narrative involvement begins when a Deco malfunction draws Berry’s observation. This encounter leads Berry to the Yurei Detective Club, a covert group of "socially dead" individuals. Hack operates as a key member, investigating Phantom Zero and societal anomalies. Early events include capture by authorities and a staged death with Berry to escape, resulting in their legal declaration as deceased and full integration into the ghost underclass. Within the club, Hack works under Finn’s leadership until tension arises over Finn’s concealed non-Phantom Zero agendas. The partnership with Berry forms the core dynamic, evolving from friction to collaboration despite trust and privacy conflicts. Technological expertise proves vital during the Phantom Zero pursuit, uncovering truths about the island’s infrastructure—including "Mark Twain," a floating uncensored data repository. The climax reveals Phantom Zero was created by system overseer Injunction Jo to instill humanity. Jo selects Hack as successor, citing perceived naivety and purity of heart. In this role, Hack halts information censorship and integrates the Yurei population into mainstream frameworks. Hack employs various gadgets alongside the robot Pup, who communicates non-verbally via emoticons and sounds understood by associates.