The Execution Division Master is a tall, imposing figure, standing at 190 cm, making him the second tallest character in Akudama Drive, just 10 cm shorter than the Brawler. He wears the standard white military uniform of the Kansai Police Execution Division, signifying his rank and authority. His uniform includes a black bandana-style mask that covers the lower half of his face, adding to his intimidating presence and reinforcing his stoic persona.

Beneath the mask, he bears a distinct scar running across his left cheek, a visible mark of his combat experience. He has grey-blue eyes and grey hair, with a long fringe draped over the right side of his face. Like other Executioners, he carries an energy sword, which rests on the left side of his uniform when not in use, ready for quick access during combat. His composed appearance and militaristic style reflect his professionalism and lethal efficiency in the field.

The Execution Division Master is characterized by his ruthless efficiency and unwavering confidence, earning him the codename “Conviction.” He approaches his duties with a cold, methodical precision, showing no mercy when carrying out executions, particularly against high-level Akudama. His composure in combat and sharp instincts reflect his status as a seasoned veteran, and his confidence occasionally borders on arrogance though it is largely justified by his extensive experience and skill.

The Master rarely speaks unless necessary, typically using his words to issue commands to his apprentice or to deliver dry, sardonic remarks during confrontations. He upholds a strict standard of discipline, expecting the Execution Division Apprentice to act decisively and with competence. He often instructs her to handle tasks swiftly and without hesitation, urging her to “take out the trash quickly.”

Although strict, the Master displays a protective and supportive side toward his apprentice. He is willing to intervene in battle when her safety is at risk and is understanding of her shortcomings, choosing to guide rather than reprimand unnecessarily. His mentorship balances firm instruction with a genuine intent to help his apprentice mature into a capable Executioner.

The Execution Division Master is a long-serving veteran of the Kansai Police Execution Division, identified by the designation No. 658. Known for his strong sense of justice and composed presence in high-risk situations, he is highly respected among his peers for his reliability and combat effectiveness. While outwardly firm and stoic, he privately reflects on his past, often seeing a younger version of himself in his zealous subordinate, the Execution Division Apprentice, whose fiery determination to eliminate Akudama mirrors his own early days.

In his youth, the Master once served as an apprentice Executioner, and during a confrontation with a particularly powerful Akudama, he sustained a wound to his left cheek, a scar that he still bears. During that same battle, he became too engrossed in the thrill of combat, which ultimately led to the death of his own mentor. This formative experience deeply shaped his approach to mentorship, instilling in him the importance of control, discipline, and not allowing personal excitement to compromise the mission or the safety of one’s comrades.

The Execution Division Master is regarded as one of the most formidable combatants in Akudama Drive, possessing unparalleled skill in martial arts and hand-to-hand combat. His abilities surpass those of any other character in the series, including the physically dominant Brawler and his own apprentice. He combines elite-level physical strength, agility, and reflexes with expert technique, allowing him to overwhelm opponents with precision and efficiency.

In battle, he maintains a calm and focused mindset, enabling him to analyze and adapt to threats even in chaotic or high-pressure situations. When fighting seriously, his presence becomes overwhelming, and even the most dangerous Akudama struggle to counter or survive his attacks. His reputation as a relentless and near-invincible enforcer of the Execution Division is solidified through multiple confrontations where he dominates enemies with calculated, near-effortless control.