Kafka was originally known as Uten, a name that he later discarded. He serves as a prominent antagonist in the early narrative and is a former member of Simeon's Elite Four, a group of high-ranking and powerful individuals within the Simeon organization. At twenty-one years of age, Kafka is a young man who holds a position as an executive of Simeon and is a direct subordinate of the organization's leader, Adam Arclight. He also acts as the captain of a special intelligence unit known as the Akarasu部队 or Akarasu Squad, which specializes in espionage and information gathering.

Physically, Kafka is depicted as a tall individual with black hair that reaches his neck and distinctive green eyes. His demeanor is that of a cold and professional operative, carrying out his missions with a detached sense of purpose. This personality is evident when he confronts the young Cruz Schild, toying with him and asking for information about the priest Adam Blade before preparing to execute him without hesitation. He finds little challenge in such prey, quickly becoming bored with the task.

Kafka's primary motivation in his appearance is to pursue and eliminate Cruz Schild, a survivor of a failed uprising against Simeon. He is sent by the organization to clean up loose ends, and he approaches this mission with confidence in his own abilities. His role in the story is that of an early formidable obstacle for the protagonist, Adam Blade. He serves to demonstrate the power of Simeon's elite operatives and to create a high-stakes situation that forces the main characters to act. He directly confronts Cruz and then engages Adam Blade, Eve Neuschwanstein, and Gido when they arrive to rescue the boy.

Key relationships in his brief but impactful appearance are primarily adversarial. He is a servant of Adam Arclight, the head of Simeon, and acts on his orders. His main conflict is with Adam Blade, whom he initially views as a target to be eliminated. Kafka is confident in his abilities, referencing the Buddhist parable of The Spider's Thread and claiming that only a god could cut the strings he produces. This arrogance leads to his downfall when Adam Blade not only easily breaks his threads but also learns to use the same ability against him. He also briefly threatens Cruz Schild, using the boy as a potential hostage, though this tactic proves ineffective against Blade.

Regarding his development, Kafka does not undergo a significant personal transformation within the story. Instead, his purpose is to be a challenge that the protagonist overcomes, leading to Blade's own development. Blade’s ability to break Kafka’s strings and then replicate his power showcases the protagonist's unique learning capability and sets the tone for future battles. Kafka is ultimately defeated by Blade, who uses his newly acquired thread powers against him.

Kafka’s notable abilities stem from being a Needless, a human with special powers called Fragments. His Fragment is known as Kandata String, which allows him to shoot powerful, razor-sharp threads from his fingertips. He can use these threads in various ways, such as binding and restraining opponents or unleashing a devastating multi-directional attack called Tempest Thread, which fires hundreds of thousands of hardened strings. The threads are incredibly durable, and Kafka possesses a high degree of regenerative capability, making him difficult to kill. His combat speed and reactions are superhuman, being compared to a younger Adam Blade.