Kazuhiko Satō, a 16-year-old first-year student in Class A at Suginami Second High School, is widely recognized by his nickname "Ippiko." Renowned for his approachable nature and selfless demeanor, he enjoys immense popularity despite unremarkable academic or athletic prowess. His defining traits—adaptability and a readiness to prioritize others’ safety over his own—drive his choices.

During a critical juncture, Ippiko covertly secures the clandestine "Explosion Rights," deploying them to trigger a power plant’s destruction at point-blank range. This sacrifice, initially perceived as fatal, becomes a catalyst for resistance against the narrative’s tyrannical game mechanics. His survival is later unveiled through the "Stop Rights," enabling his return as a linchpin in the rebellion to dismantle the system, notably confronting the Queen’s regime.

Outside the central plot, he surfaces in supplemental 8-panel comics, trading gravitas for comedic antics in absurd school mishaps or playful clashes with allies. Standing 168 cm tall and weighing 58 kg, he carries blood type O, with a Taurus zodiac marking his April 28 birthday.