Sōichirō Hague started as an ordinary firefighter, ascending to Battalion Commander and Captain of Special Fire Force Company 4. His leadership commanded deep respect across the organization, especially for mentoring subordinates such as Pan Ko Paat. He instilled in them that a firefighter's survival was essential to saving others, prioritizing calmness and compassion in operations. During the Great Disaster of Year 196, he gained three distinctive facial scars. This catastrophe also activated his first Adolla Link—a tie to the series' metaphysical dimension—which transformed his perspective. It liberated him from lingering guilt over past failures to save lives but ignited an obsession with the Adolla Burst phenomenon. He privately considered founding a religion from his revelations and actively pursued re-experiencing the Adolla Link, even asking Shinra Kusakabe to burn him alive to reignite the connection. Lacking pyrokinetic abilities, Hague fought using extraordinary physical strength and expert handling of firefighting gear. He employed axes with lethal precision and deployed safety wires to immobilize foes rapidly, tactics enabling him to battle enhanced enemies despite his age. His endurance allowed him to survive severe injuries, though his altered psyche drove him to intentionally absorb damage in combat to feel pain. Hague was instrumental in establishing Company 7 in Asakusa, convincing the reluctant Benimaru Shinmon and Konro Sagamiya to assume their roles. Later, his Adolla Burst knowledge made him a target in the Stigma arc. He was assassinated in his office by the White-Clad operative Gold, who impaled him with metal shards and disguised the killing as suicide. Shinra sensed his death instantly through their Adolla Link, and Fire Force investigators later confirmed it as homicide. After the second Great Cataclysm, Shinra Kusakabe's spacetime manipulation reversed global devastation and resurrected the dead, including Hague. He shared a close family relationship with his granddaughter, Asako Hague, Captain of Company 6.