Kufa is depicted as a calm and composed individual, especially when carrying out his duties as an assassin. His outward professionalism, however, is often tested by his growing attachment to Melida Angel, which causes him to act more emotionally and at times irrationally. For instance, he rejected Rosetti’s attempt at camaraderie when she extended goodwill as a fellow tutor of the Angel family. His encounters with figures such as Williams Gin and Black Madia also reveal a willingness to take significant risks when Melida’s safety is involved.

As Melida’s tutor and attendant, Kufa prioritizes her growth and protection above his obligations to the Guild White Knight, even betraying his original mission to support her. While some view his teaching style as harsh or even sadistic, Kufa himself denies such claims. His rigorous methods, however, earned him a reputation within the Angel household as a “brutal” teacher. At St. Friedeswiedes Academy for Girls, where he is the only male permitted, his devotion to Melida has unintentionally attracted the admiration of other students.

Beneath his strict exterior, Kufa occasionally reveals a more reflective side, sharing stories with Melida about his late mother. His recollections highlight the struggles they faced as Night citizens and his admiration for her resilience, which continues to shape his outlook and motivations.

Kufa is described as a tall man with dark purple hair and heterochromatic eyes, one resembling a Martinique hue and the other an East Side blue. His standard attire is a military-style uniform, which emphasizes his role within the Guild White Knight; this is noted by a pedestrian in the episode The Last Testament of a Certain Skeleton.

When drawing upon his vampiric heritage, Kufa undergoes a dramatic transformation: his hair turns long and white, his eyes glow a more intense shade of blue, and sharp fangs emerge. In his further “awakening” form, these features become even more pronounced, his hair lengthens, his nails sharpen into claws, and his eyes turn pitch black with luminous pupils, signifying the full unleashing of his vampiric power.

In addition, Kusanagi is depicted as an avid smoker and frequently speaks in a Kyoto dialect, further distinguishing his mannerisms from other members of the clan.

Kufa was born as a half-human, half-vampire, a rare existence considered taboo within the rigidly stratified society of Assassin’s Pride. His heritage tied him to the Night Clan, a group of citizens often feared and discriminated against, which shaped much of his early life. Raised by his mother under harsh circumstances, Kufa developed a deep respect for her resilience and often recalls her sacrifices as a source of personal strength.

As he matured, Kufa was recruited into the Guild White Knight, an organization tasked with maintaining order and guiding noble families. There, he distinguished himself as the strongest member of the Lancanthrope class, mastering abilities far beyond those of ordinary tutors or assassins. Despite his loyalty to the guild, he was eventually assigned a secretive mission regarding Melida Angel, a noble girl suspected of lacking mana. His orders were to evaluate her worth and, if she proved talentless, to assassinate her.

Confronted with Melida’s determination and spirit, Kufa defied his guild’s expectations, choosing instead to support her growth. This decision marked a turning point in his life, forcing him to navigate the conflict between his duties as an assassin and his new role as Melida’s protector and mentor.

Kufa’s primary weapon is a long-bladed sword resembling a katana. The weapon features a black-and-gold guard on its hilt, with a black grip accented by golden details. Its design is completed by a simple golden pommel, giving it both elegance and practicality. As an assassin, Kufa wields the blade with precision and efficiency, complementing his vampiric strength and refined combat skills.

Melida Angel
Kufa was assigned to act as Melida’s tutor under strict orders from “Father”: if she showed no talent for mana, he was to assassinate her. However, upon witnessing her determination to prove herself as a legitimate member of the Angel household, Kufa defied his orders. Believing her potential would be wasted, he performed a transplant procedure that granted her the ability to wield mana, an act that endangered both of their lives.

As her instructor, Kufa subjects Melida to rigorous training designed to help her eventually surpass him, even stating that if the day came when she needed to kill him, he would willingly give her his life. Although his teaching methods are harsh, he recognizes her rapid progress and gradually develops a deep bond with her, finding hope in her presence. Over time, Kufa becomes fiercely protective of Melida, regarding her happiness as paramount. In the manga, he remarks during the Luna Lumiere tournament that making Melida sad is “a crime.” In the anime adaptation, it is revealed that he asked Black Madia to watch over her should anything happen to him.

Rosetti Pricket
Rosetti, a fellow tutor under the Angel household, initially clashes with Kufa after a poor first impression when he inadvertently insulted her. Despite this rocky start, the two cooperate during missions to protect the Angel family.

Flashbacks reveal a deeper connection between them from childhood. While under the care of Marquis Blossom Pricket, Kufa met Rosetti when she was gravely injured. Unable to let her die, he transformed her into his Kin. Later, he struck a deal with Father and the Guild White Knight: in exchange for his allegiance, Rosetti’s memories would be erased, allowing her to live in the light while forgetting their bond. Though outwardly detached, Kufa revealed his inner pain when Rosetti expressed a desire to remain by his side, warning her, “it’s cold over here,” symbolizing the isolation he felt in losing her. Despite her erased memories, Kufa continues to treat Rosetti as a younger sister and remains protective of her.

Elise Angel
Elise, Melida’s cousin, views Kufa with both gratitude and rivalry. While thankful for his efforts to support the Angel household, she often perceives him as a competitor for Melida’s affection, especially since Melida frequently praises him. Although Kufa is aware of Elise’s hostility, he is nonetheless pleased to see her restore her close bond with Melida after the Luna Lumiere Selection. During her own training with him, Elise experiences his harsh methods firsthand and refers to him as “the Devil,” reflecting his reputation as a strict, uncompromising teacher.

Amalia
Amalia, Kufa’s late mother, played a significant role in shaping his character. Although her name is not revealed until his return to the Night World, she is remembered by Kufa as a figure of strength who endured hardships as a refugee. He often shares memories of her with Melida, expressing both admiration and longing. Amalia is buried beside the orphanage in Shangarta village, and her legacy remains a source of inspiration and emotional grounding for Kufa.