Yūichirō Kurono serves as the chief of Haijima Industries' Power Development Facility and guardian of the Sixth Pillar. This 29-year-old former Third Generation pyrokinetic stands 177 cm tall and weighs 69 kg. He possesses short black hair, angular pale yellow eyes with sharpened pupils, and a charred right arm—a consequence of overheating his body—typically concealed beneath white bandages he unwraps before combat. His attire consists of a plain grey collared shirt, a black tie featuring a white shinigami-esque skull tie pin, long black pants held by a white skull belt, and black shoes. Kurono's personality centers on an intense obsession with weakness, earning him the moniker "The Maddest" as a counterpoint to Benimaru Shinmon's "The Strongest." He champions a world where the strong are protected and the weak crushed, frequently provoking or tormenting those he deems weak to gauge his strength without personal risk. This tendency causes him to underestimate opponents who show resolve instead of fear. Despite his aggression, he rigidly follows orders from Haijima leadership, considering himself a "company man" who maintains politeness towards superiors while displaying open hostility towards peers. He occasionally complains about his wages and contemplates changing jobs. Paradoxically, he believes weakness is temporary and should be cherished before individuals grow stronger. His background includes treatment for Tephrosis at Haijima Industries, where he encountered a young Shinra Kusakabe. Kurono requested to stay at the facility despite his notoriety and later joined its skill development division. During this time, he expressed a desire to "play with the children," which Shinra interpreted as malevolent. Kurono's pyrokinetic ability generates Black Smoke reaching 130°C (266°F). He detects movement within this smoke and conceals himself inside it. He can force the smoke into victims' bodies, causing fatal internal combustion. He solidifies it into weapons like kunai, knives, spears, swords, and scythes, wielding them with exceptional speed and skill. By coating these weapons in flames or manipulating smoke density, he propels himself through the air or rides on smoke plumes. His physical prowess allows him to lift adults one-handed, and he is a proficient swimmer. His combat skills and power are considered equal to Benimaru Shinmon's, though he prefers targeting weaker foes unless ordered otherwise. During the Haijima Industries Arc, Kurono conducted combat tests with Nataku Son and battled Shinra Kusakabe, ignoring researchers' orders to stop. When Company 8 infiltrated the facility, he prioritized attacking perceived weaker members like Tamaki Kotatsu and Iris until White Clad operatives intervened. He later assisted in rescuing Nataku from a Flame Giant, calming the boy by affirming the value of acknowledging weakness. In the Stone Pillar Arc, Kurono assisted against a titanic Infernal emerging from the ocean. He saved Shinra from drowning but considered abandoning him to avoid a difficult fight until Juggernaut intervened. He ultimately severed the Infernal's arm, triggering an ignition of its ashen remains. Throughout the Asakusa Showdown and Final Pillar arcs, he collaborated with Company 2 to destroy multiple Titanic Infernals using combined tactics, though he grumbled about the challenges of fighting strong opponents and stagnant wages. During the confrontation with the Eighth Pillar, he observed Shinra's arrival with detached amusement. Kurono perished during the Great Cataclysm but was restored to life when Shinra Kusakabe rewrote reality. Trivia notes state the kanji for his surname (黒) means "black," aligning with his Black Smoke ability, and his skull motifs may reference Death from *Soul Eater*.