Akihito was born to a human mother and an immortal Youmu father, making him a Half-Youmu. His abilities include rapid regeneration and fire manipulation, suggesting that his father was an exceptionally powerful Youmu.

As a child, Akihito was involved in a car accident but emerged completely unscathed, an event that revealed his inhuman resilience. This incident caused fear and alienation from those around him, leaving him isolated during his early years.

Little else is known about his past, but his first meeting with Hiroomi and Mitsuki Nase proved pivotal. During this encounter, he was gravely injured by Miroku Fujima, which triggered the awakening of his Youmu side. In his uncontrolled state, Akihito nearly killed Hiroomi. To prevent similar incidents, the Nase family established a deal to monitor him closely and minimize the risks posed by his Youmu nature.

Akihito is a young man of average height with a lean build. He has short blond hair swept slightly to the left and brown eyes with a gentle downward tilt (tareme), giving him a mild and approachable expression despite his Half-Youmu nature.

He is most commonly seen wearing his school uniform, which consists of a white shirt, red tie, navy blazer, and gray slacks. Outside of school, his casual outfits are generally simple, often consisting of sweaters, cardigans, and collared shirts paired with jeans, reflecting his easygoing personality.

When his Youmu side manifests, Akihito’s appearance undergoes notable changes: his eyes glow a bright gold, his pupils slit like those of a predator, and his demeanor becomes far more menacing. These physical shifts signal the loss of his self-control as his Youmu powers begin to take over.

Akihito is portrayed as playful, friendly, and somewhat sarcastic, though he is also sincere and caring toward those close to him. One of his most distinctive traits is his fascination with glasses; he often refers to girls who wear them as “bespectacled beauties” and even jokingly describes himself as a meganest, an extreme enthusiast of glasses.

Despite his lighthearted and humorous demeanor, Akihito demonstrates empathy and a strong sense of responsibility, particularly when it comes to protecting others from danger. His optimism and teasing nature often serve to ease tension, though he can also be reckless, especially when dealing with threats related to his Half-Youmu powers.

Half-Youmu Physiology
As the child of a human mother and an immortal Youmu father, Akihito possesses traits from both lineages, giving him abilities far beyond those of an ordinary human.

Regenerative Healing Factor
Akihito can recover rapidly from nearly any injury, including otherwise fatal wounds, making him effectively immortal.

Transformation
When critically injured, Akihito loses control as his Youmu side emerges, transforming him into a feral state. In this form, his eyes turn black with a multicolored iris, his blond hair develops green highlights, and his body is surrounded by an unexplained green energy. This transformation significantly increases his combat power but comes at the cost of his self-control.

Combat Abilities:

• Immense Strength: Even without full transformation, Akihito demonstrates superhuman strength, capable of stopping weapon strikes or powerful kicks with a single hand.
• Earth Manipulation: During his battle with Mirai, he generated an earthen wall, suggesting limited geokinetic ability.
• Pyrokinesis: He can create and manipulate fire, powerful enough to break through strong barriers and cause large-scale destruction within a wide radius.
• Electrokinesis: In his transformed state, Akihito channels green electricity into his attacks, such as a charged fist capable of devastating impact.
• Resistance to Spirit World Techniques: In the films, Akihito demonstrated resilience against the sealing powers commonly used by Spirit World Warriors.

Beyond the Boundary Power
Within the Beyond the Boundary itself, Akihito harnessed his Youmu essence directly, fighting alongside Mirai while channeling destructive energy through his hand that contained his suppressed Youmu powers.

Mirai Kuriyama
Despite their rocky first meeting where Mirai repeatedly attempted to kill him, Akihito treats her kindly and gradually forms a close bond with her. He supports her growth as a Spirit World Warrior, partly out of empathy for her struggles, which mirror his own. Over time, Mirai develops romantic feelings for Akihito, and by the end of the series, it is strongly implied that he reciprocates. He admits that a future without her would be meaningless and expresses his desire for her not to sacrifice herself for his sake. Several moments highlight his affection, such as blushing when she attempts to kiss him and confessing in the finale that he loves “the bespectacled beauty, Mirai.” Their relationship is further reinforced in Beyond the Boundary Movie: I’ll Be Here, where they acknowledge their mutual feelings.

Hiroomi Nase
Hiroomi is Akihito’s closest friend and upperclassman. Their first meeting was marked by danger when Akihito’s Youmu side nearly killed Hiroomi, leading the Nase siblings to monitor him closely. Over time, the two developed a genuine friendship, often engaging in playful banter. Hiroomi affectionately calls Akihito “Akkey,” a nickname that embarrasses him, and frequently teases him with antics such as sticking his hands under Akihito’s arms. Despite the teasing, Hiroomi demonstrates genuine concern for Akihito’s well-being.

Mitsuki Nase
Akihito shares a comedic tsukkomi-boke dynamic with Mitsuki, where she often calls him out for his eccentricities, particularly his obsession with “bespectacled beauties.” While Mitsuki frequently ridicules him, she also shows care for him, having protected him during their early encounters. Though she often downplays it with sarcasm, Mitsuki respects Akihito and contributes to supporting him when his Youmu side threatens to surface.

Yayoi Kanbara
Yayoi is Akihito’s mother, who remains a presence in his life despite living far away. She regularly sends him postcards and eventually visits after the events of Episode 10. While her playful antics often irritate Akihito, she also reveals a more intimidating side, particularly when she uses her Spirit World Warrior abilities to protect him. Their relationship blends humor and tension, though Akihito acknowledges her importance, telling her that one day she should share more about his heritage and himself.

The given name Akihito (秋人) is composed of aki (秋), meaning “autumn,” and hito (人), meaning “person.” His surname Kanbara (神原) combines kan (神), meaning “god,” and hara/bara (原), meaning “field” or “plain,” which can be interpreted together as “fields of the gods.”