Kaïm is a demon from the original Devilman manga, identifiable by his massive size and distinct physical form. He is a large, quadrupedal beast-like demon, measuring approximately nine meters in length and three meters in height, with enormous horns protruding from his broad shoulders. His appearance is imposing, yet his actions reveal a nature that defies the typical demonic characterization of being driven solely by combat and violence.

Personality and motivations are at the core of Kaïm's significance in the story. While most demons in the series are portrayed as creatures who live only for battle, Kaïm possesses a singular devotion: his love for the demon warrior Sirene. This love is the primary driver of his actions. When Sirene is left near death after a fight with Devilman, Kaïm arrives with other demons to rescue her. Fully aware of the consequences, he selflessly offers his own body to her for the purpose of fusion, a process that would grant her the power to continue fighting. He explicitly states he has no intention of surviving, explaining that his only desire is to let her experience the thrill of victory over Devilman. In a final, poignant act, Kaïm uses his own tail to sever his head, sacrificing himself completely so that his body may serve Sirene. His last words to her are a declaration of her beauty, even covered in blood, cementing his role as a tragic figure who embodies self-sacrifice for love.

In the narrative, Kaïm serves as a pivotal catalyst for a major confrontation. After his sacrifice, Sirene fuses with his lower body, transforming into a powerful centaur-like form that gains the upper hand against Devilman, impaling him with Kaïm’s massive horns and nearly defeating him. Though the fused demon ultimately perishes, the scene carries a unique emotional weight. Devilman later finds their fused body, still standing, with Sirene’s face wearing an expression of satisfaction and triumph in death. This moment leaves a profound impression on Devilman, who sees something resembling beauty and love in their final stance.

Key relationships are centered on Sirene. Kaïm’s entire existence within the story revolves around his love for her, and his bond is the primary reason for his brief but impactful appearance. He has no direct interaction with Devilman before his death, as his role is to empower Sirene to be a more formidable opponent. However, his sacrifice is not forgotten; later in the manga, other demons reference avenging Kaïm, indicating he was respected among his kind.

Regarding development, Kaïm has a very limited but powerful arc contained within a few pages of the manga. He begins as a rescuer and ends as a willing sacrifice. In later derivative works, his story is expanded upon. In the manga sequel Devilman Lady, Kaïm and Sirene appear together in Hell, and Kaïm’s consciousness is shown to still be devoted to her. An OVA series, CB Chara Nagai World, reinterprets him as a reincarnation of the demon Amon’s soul, providing an alternative explanation for his deep connection to Sirene.

Notable abilities are not displayed by Kaïm individually, as he never fights on his own in the original story. His physical traits are his immense size, strength, and his large, powerful horns, which he can use for a high-speed charge. When fused with Sirene, his body grants her enhanced abilities, including the power to generate powerful electrical discharges between his horns for offensive attacks.