Soichiro Hague captained Special Fire Force Company 4. Beginning as a regular firefighter, he transitioned early into a Special Fire Soldier, earning widespread respect throughout the Fire Force for his bravery and leadership. His experience and wisdom made him a revered figure among peers and subordinates. He was the grandfather of Asako Hague, Captain of Company 6. His face bore three prominent, claw-like scars sustained during the Great Disaster 250 years before the main events. These scars later became significant, facilitating an Adolla Link—a connection to a fiery otherworldly dimension. He typically wore round glasses and maintained a gentle demeanor despite his advanced age. Initially kind and level-headed, his personality shifted drastically following the Adolla Link experience. This connection instilled a compulsive masochistic desire, an obsession with experiencing intense pain or burns to reestablish contact with Adolla. He actively sought out powerful pyrokinetics like Shinra Kusakabe, pleading to be burned by Shinra's Adolla Burst. Though a non-powered human, he compensated with high-level physical combat skills and specialized mechanical contraptions for subduing foes. His extensive knowledge of the Adolla Link and Adolla Burst phenomena made him a rare source of insight into these mysteries. A pivotal storyline occurred during Season 2. In an encounter with Shinra, Hague deliberately provoked the youth to unleash his Adolla Burst, driven by his desperate yearning to return to Adolla. The confrontation escalated into a battle where Arthur Boyle intervened, defensively exploiting Hague's masochistic tendencies by using his body as a shield, highlighting Hague's psychological deterioration. His narrative concluded when assassins from the antagonistic White-Clad organization killed him. This happened concurrently with Shinra Kusakabe's training arc in Asakusa following an underground conflict against the White-Clad. His death marked a significant loss for Company 4 and the broader Fire Force, leading to the appointment of a new captain. His legacy endured as a pioneering figure who bridged conventional firefighting and the specialized role of the Special Fire Force. His tragic transformation and demise served as a cautionary illustration of the Adolla Link's corrupting influence on individuals lacking innate Adolla Burst capabilities.