Fukurou is the twenty-seven-year-old version of Isami from the future dimension of La'cryma. He holds the rank of a Dragon Knight, a protector of his crumbling reality, and his name translates to "owl" from Japanese, following the avian naming pattern of his comrades. In terms of physical appearance, Fukurou is tall and muscular with a long brown ponytail. His most distinguishing feature is the loss of one eye, which he presumably lost during the gang wars of his teenage years; a prominent scar runs over the empty socket and down across the left corner of his mouth.

While many of the Dragon Knights from La'cryma are defined by their grim fatalism, Fukurou stands apart due to his easygoing and humorous personality. He embodies a laid-back, almost zen-like attitude, often encapsulated by his personal motto to not worry about things. Unlike his close friend Karasu, who is the future version of Yu, Fukurou is not tormented by his existence. Instead, he views the present-day timeline with a sense of fondness and relief rather than pain, looking warmly upon the younger versions of his friends, including Ai, Yu, and his own younger self, Isami.

Fukurou’s primary motivation stems from loyalty and friendship rather than abstract duty. When Karasu was declared a traitor to La'cryma, Fukurou was ordered to execute him. He deliberately failed this mission, choosing instead to aid his best friend and defect from their original cause. His actions are consistently protective; he seeks to safeguard the past to ensure a different outcome for the future during the series' events. This is particularly evident in his relationship with the younger versions of the characters. He serves as a protective guardian for the children, specifically admonishing Yu and his own younger self to remain friends, a bond he clearly values as essential. He also shares a deep bond with the future version of Ai, a friendship that carries significant emotional weight for him.

Within the story, Fukurou acts as a stabilizing force and a direct counterpart to the more intense and volatile Karasu. While Karasu is often cold and distant, Fukurou provides warmth and tactical support. His role becomes critically tragic due to the fluid nature of time in the narrative. In a previously observed potential future, it was foreseen that Karasu would kill Fukurou. However, after the protagonist Haruka uses her powers as the Dragon Torque to alter the course of fate and change that potential future, the entity Noein intervenes directly. Instead of Karasu committing the act, Noein kills and absorbs Fukurou, solidifying his demise as a direct consequence of the timeline being altered. As he faces his death, his final expressed wish is to see the future Ai one more time, highlighting that his relationships were his highest priority.

As a Dragon Knight, Fukurou possesses a range of supernatural abilities. He can traverse dimensions and stop time within localized areas. In combat, his signature weapon is a spin weapon that manifests not as a physical blade but as clusters of laser-like projectiles or simple energy blasts, allowing him to attack from a distance. He is shown to be a capable fighter, successfully intervening to save the children from the aggressive Dragon Knight Atori and holding his own against other threats, though he is ultimately no match for the god-like power of Noein. Despite wearing the mantle of a soldier, his personality is so markedly different from his grim surroundings that he appears to be the least lousy person among the warriors from the future.