Jako, sometimes called Jakoh, hailed from the Celestial Emperor's village and was raised as an adopted brother to Falco by Falco's mother. During Raoh's assault on the village, Raoh recognized Jako's innate malice. He dragged Jako out by the collar, warning Falco to kill him due to his inherent evil. Falco refused only because their mother was present. The incident instilled in Jako a lifelong terror of the Hokuto lineage and a deep fear of darkness, associated with the prominent North Star in the night sky. This astrophobia manifested as an obsession with constant light. He wore a generator on his back powering three lanterns and demanded excessive illumination from his enslaved populace, ignoring their suffering. Following his adoptive mother's death, Jako seized power by kidnapping the Celestial Empress Lui. He declared himself Viceroy of the Imperial Capital, ruling autocratically in her name. He exploited Falco's unwavering loyalty to the Celestial Emperor, using Lui as a hostage to force Falco into serving as his enforcer. Jako commanded his Imperial Army to conquer territories, enslave populations, and force them to generate electricity solely to sustain his perpetual light. He fathered two sons, Jask and Sheeno, who acted as his primary enforcers in the manga; the anime replaced them with the Gento Generals Boltz and Taiga. Jako perceived Hokuto and Nanto martial artists as existential threats to his supremacy, fearing they would outshine Gento's imperial star, Taikyokusei (Polaris). This paranoia grew as Kenshiro and the Hokuto Army challenged his empire. When his subordinate Shoki attempted to assassinate him out of moral outrage, Falco intervened to maintain the appearance of loyalty, though Jako's son Sheeno (or Boltz in the anime) fatally wounded Shoki during the escape. The subsequent deaths of his enforcers, including Sheeno by Kenshiro, intensified Jako's descent into hysterical violence. He lashed out indiscriminately, stabbing his own son Jask (or Taiga) and murdering subordinates for minor failures like leaving him in darkness. In a final act of treachery, Jako trapped Kenshiro, Falco, their allies, and Empress Lui in an underground chamber and triggered a landslide to bury them alive. Though they escaped, Jako ordered projectile bombardments targeting the weakened fighters. When Empress Lui was freed, nullifying Falco's obligation to obey, Jako attempted to flee. Kenshiro redirected a surge of water that swept Jako toward Falco. Desperate, Jako begged Kenshiro for mercy, proposing a duel against Falco for his freedom. Kenshiro agreed, but Jako's opportunistic attack with a projectile weapon failed. Falco executed him by igniting his body with Gento Koken's energy, incinerating him while recounting his crimes. The anime adaptation shows Kenshiro dislodging debris that caused flooding to drag Jako underwater after his own soldiers abandoned him. Jako's personality was characterized by cowardice, tyranny, and selfishness. He ruled through fear and manipulation, hiding behind the Celestial Empress's authority while treating even his own sons abusively. Arrogance surfaced when he held leverage, but he collapsed into panic or violent outbursts when threatened. His fear of darkness often triggered irrational behavior, including killing subordinates over trivial lighting issues. When cornered, he resorted to pitiful pleas for forgiveness or offers of reconciliation with those he had betrayed.