Zanka was born into the distinguished Nijiku family, a household with a long tradition of producing Hell Guards. Following family expectations, he was enrolled in the Central Hell Guard Training Academy, where he quickly rose to the top of his class. His talent and lineage earned him praise from peers, who regarded him as someone with “gifted blood” and destined for greatness. Confident in his abilities, Zanka sought the honor of sitting on the golden throne, a distinction awarded to the most outstanding trainee of the year.

Despite his outward pride, Zanka worked relentlessly in secret, determined to surpass his classmates. His confidence was shattered, however, when a new trainee named Hyo joined the academy. Though raised in the slums, Hyo displayed extraordinary skill and soon surpassed every member of her class, including Zanka. The loss devastated him, he vented his frustration by slamming his head against a wall until it bled, insisting to himself that he was still “the best.” Hyo overheard his outburst and confronted him, pointing out that his pursuit of the golden throne was rooted not in strength but in a desire for validation. Her words forced Zanka to reflect on his motives and acknowledge that he was not as unique as he believed.

This realization deepened his disillusionment. When students were given the chance to select their weapons, Zanka chose a battered stick, thinking it would distinguish him. He later discovered it had been placed there by mistake, leaving him embarrassed. By contrast, Hyo selected a simple katana, underscoring her focus on effectiveness rather than appearance. Ashamed, Zanka abandoned the academy and wandered into a well, where he remained without food or water for three days, clutching the same stick.

At the bottom of the well, Zanka encountered Enjin. Confessing his failures, he referred to himself as a “loser” and an “average Joe.” Enjin countered by encouraging him to embrace his ordinariness, telling him he could be “an average Joe who’s better than a genius.” Pointing out Zanka’s attachment to the stick, Enjin inspired him to recognize his weaknesses as a path to growth. Reinvigorated, Zanka climbed out of the well, ready to pursue strength anew.

Although his family disowned him for becoming a Giver, Zanka went on to join the Cleaners, forging his stick into his personal Vital Instrument. Under Enjin’s leadership in Team Akuta, he honed his skills further. In one notable instance, he singlehandedly defeated a moose-like Trash Beast in the North Ward despite still being a trainee, earning Enjin’s praise for his determination and growth. Later, he is depicted sharing a celebratory meal with Enjin and Gris, symbolizing his acceptance into his new family.

Zanka is depicted as a tall, slender teenager with a sharp and carefully maintained appearance. He wears his dark brown hair slicked back into a mullet, accented with blond streaks that highlight his piercing navy-blue eyes. His distinctive features include eyebrows shaved into a three-line pattern and long tassel earrings that dangle from his pierced ears, giving him a striking and memorable look.

His Cleaner’s uniform stands out for its ceremonial flair and attention to detail. Unlike the standard issue worn by most of his peers, Zanka’s outfit is considerably looser in cut, with wide, open sleeves and baggy pants designed for freedom of movement. The shoulders are slightly raised, and a long navy-blue sash is tied at the waist, draping both in front and down his back. A large utility bag is fastened at his waist, supported by a sash that crosses over his chest, consistent with the functional needs of a Cleaner.

What distinguishes Zanka’s uniform most is its refinement and elevated quality. His Cleaner’s badge is crafted with far more extravagance than the standard version, symbolizing his elevated status. This added polish reflects his background as a “young master” in the Ground, a heritage that lends him a sense of sophistication and distinction among his peers.

Zanka presents himself as calm and composed, a façade that conceals the emotional turbulence he often experiences internally. Beneath this reserved exterior, he wrestles with feelings of anger, frustration, and insecurity, which can erupt into sudden and dramatic outbursts. Though he strives to maintain a serious and collected image, he is often swept up in the antics of his more eccentric teammates, briefly dropping his no-nonsense behavior. His teammate Tomme Mima has described him as one of the few members capable of restoring order, noting Zanka’s ability to “knock any sanity” into the group when needed. His communication style blends politeness and confidence with blunt sarcasm and sharp candor, delivered in a distinctive Chūgoku dialect.

As a former member of the Nijiku family, Zanka carries himself with a sense of pride rooted in his noble background, though he avoids outright arrogance. His worldview is shaped by a personal distinction between “average” individuals and “geniuses.” Once considering himself among the latter, his humiliating defeat by Hyo forced him to confront his limitations and acknowledge himself as “average.” This experience left him with a deep-seated resentment toward geniuses, whose effortless talent he envies, though he treats them with outward cordiality and attempts to hide his jealousy, particularly in his interactions with Hyo and Rudo.

Having accepted his status as “average,” Zanka is now motivated by the determination to surpass geniuses through sheer perseverance. Enjin observes that this pursuit is not truly a rivalry with others but a personal battle against Zanka’s own weaknesses, which fosters his resilience and mental strength. Zanka refuses to blame others for his failures and rejects pity, demonstrating a maturity that sets him apart. His sharp observational skills and critical thinking make him a valuable strategist for the Cleaners, to the point that even Arkha Corvus relies on his insights, particularly regarding the mysteries surrounding Rudo and the Hell Guard. His mix of discipline, intelligence, and pragmatism has earned him the respect of his peers and cemented his role as one of Team Akuta’s most dependable members.

Enjin
Zanka holds deep admiration for Enjin, who inspired him to abandon his Hell Guard training and instead join the Cleaners. He works diligently to earn Enjin’s praise, often expressing joy when he receives it, and consistently regards him with respect. While Zanka can be teased by Enjin to the point of irritation, others observe that he tends to be soft when it comes to Enjin, sometimes calling him a “pushover.” Their bond is both mentor-student and brotherly, built on mutual understanding and trust, and they often speak as equals when addressing serious matters.

Rudo Surebrec
Zanka initially becomes Rudo’s mentor at Enjin’s request, but their relationship begins awkwardly, with tension and a lack of compatibility. Their first sparring match only reinforces this disconnect, and a later incident complicates matters further. Nevertheless, Zanka fulfills his responsibility as a mentor by identifying the conditions under which Rudo’s Vital Instrument would manifest, a pivotal moment in Rudo’s growth. Over time, the friction between them eases, and their dynamic evolves into a more cooperative and supportive relationship.

Riyo Reaper
As teammates within Team Akuta, Zanka and Riyo share a casual and friendly rapport, often working together smoothly during missions. However, Riyo’s playful and teasing personality sometimes strikes Zanka as immature, leading him to view her behavior as frivolous. Despite this, he demonstrates genuine concern for her safety, especially during the Penta incident, where he was visibly distressed after Riyo was nearly killed by Amo’s powers.

Follo Tunito
Zanka indirectly influenced Follo to join the Cleaners after Follo witnessed him defeat a moose-like Trash Beast in the North Ward. Inspired by Zanka’s display of strength and determination, Follo approached Enjin, Gris, and Zanka with the request to become part of their group.

Tamsy Caines
During the Lady of Penta Arc, Zanka and Tamsy worked effectively together despite occasional clashes. Zanka grew frustrated when Tamsy appeared reckless with his abilities, openly shouting at him in confusion. Despite these disagreements, the two successfully collaborated to contain the Cleaners during the conflict, demonstrating their ability to function as a team under pressure.

Overall Abilities
Zanka is portrayed as one of the most capable combatants among the Cleaners, combining speed, strength, and agility with exceptional skill in handling Vital Instruments. His proficiency is such that even Enjin, a veteran Giver, regards him as the most talented Vital Instrument user within the organization. A former top trainee at the Hell Guard academy, Zanka received extensive training in weaponry and hand-to-hand combat before leaving the program. In addition to his academy experience, he underwent private instruction from his family, including his sister Kyouka Nijiku, who trained him to react quickly enough to dodge gunfire.

Enhanced Strength
Zanka possesses considerable physical power, capable of killing Trash Beasts, shattering stone, and breaking bones with his strikes. During his second fight with Jabber Wonger, he demonstrated this strength by lifting and hurling a massive piece of earth with his Life Instrument, forcing Jabber to defend himself with his awakened claws.

Enhanced Speed
Speed and reflexes are central to Zanka’s fighting style. He wields his Vital Instrument with remarkable precision, keeping pace with powerful opponents like Jabber. His sharp reflexes, honed through his sister’s rigorous training, allow him to evade bullets and respond effectively even to irregular or unpredictable attacks.

Great Intellect
Zanka’s tactical mind is one of his greatest assets. He has repeatedly demonstrated the ability to analyze the functions of enemy Vital Instruments in the middle of combat and quickly devise strategies to counter them. In his battle with two Raiders, he quickly unraveled their techniques and exploited weaknesses in their strategy. Against Jabber Wonger, Zanka coordinated with Rudo to combine Gris’s amulet-based Vital Instrument ability with their own attacks, landing a decisive blow on the Raider despite his overwhelming strength.

Vital Instrument Proficiency
Zanka’s expertise with Vital Instruments sets him apart from his peers. According to Enjin, he is the best handler of such weapons among all the Cleaners. His deep understanding allows him to unlock their full potential while also dissecting the abilities of opponents’ instruments to find counters. His willingness to experiment makes him an effective teacher, as seen when he guided Rudo in learning to use his powers more creatively and adaptively, particularly in their confrontation with Jabber.