B'T Jutaime is the mechanical partner of Fou Lafine, a priest and warrior known as the Spiritual Guardian of the South within the Machine Empire's hierarchy. Her design takes the form of a large, deep red bird, directly inspired by the Vermilion Bird of the South from Chinese mythology, a creature often identified with the phoenix or hō-ō bird. True to the phoenix archetype, her narrative is heavily defined by themes of death and spectacular rebirth. At one point, she suffers fatal damage at the hands of the antagonist Quattro. She is resurrected when Fou plays the song of the angels on his violin, an act that awakens her latent ability to be reborn into her true phoenix form. In this ascended state, her plumage shifts from its original vermilion to a distinctive pinkish luminescence, signifying her heightened power and purity.

Personality-wise, Jutaime is presented as a composed and loyal being, embodying the French phrase that is her namesake, which translates to I love you. This name reflects her core identity as a B't who demonstrates an unyielding and devoted love for her master, Fou. While some of her mechanical counterparts are characterized by aggression, Jutaime possesses a more serene and graceful demeanor, aligning with her elegant bird-like form. Her motivations are intrinsically linked to Fou's objectives and well-being. She actively supports him in his conflicts, particularly his personal vendetta against Quattro, and is driven by a desire to protect and serve him, showcasing a fierce independence when engaging enemies on her own.

Within the story of the B't X Neo OVA sequel, Jutaime plays a crucial role as a formidable fighter and a source of profound psychological power. Her primary role is to act as Fou's partner in battle, their combat style uniquely centered on sound. Her signature offensive technique is called Deadly Carol. This sonic attack is specifically designed to overwhelm and destroy the control system or electronic brain of an enemy B't. It achieves this by inducing terrifying hallucinations of angels and skeletons, leading to the target's mental collapse. This attack is ineffective against humans and can only be avoided by an enemy B't deactivating its own auditory sensors. Her most powerful ability, Fortune Symphonic, is an amplified technique that manifests when Fou simultaneously plays his violin. This devastating combination allows them to forge psychological and emotional connections with anyone within range, further demonstrating the deep resonance between pilot and machine.

Her key relationships are primarily with her master, Fou Lafine, and her nemesis, Quattro. The bond with Fou is absolute and symbiotic; he is the only one who can unlock her true power, and she is his most trusted ally in battle. The relationship with Quattro is adversarial and traumatic, defined by her destruction at his hands and the subsequent quest for revenge. The character's development is largely tied to this cycle of death and renewal. The story does not explore significant evolution beyond this pivotal resurrection; her transformation into the true phoenix represents the completion of her latent potential rather than an ongoing arc of change. Her combat abilities are formidable and varied. Beyond her sonic techniques, she is an independent combatant capable of pursuing and engaging adversaries like members of the Crow unit solo, using her wings and sharp claws effectively in physical combat. Her body itself possesses the characteristics of a musical instrument, which is fundamental to how she generates her sonic attacks and harmonizes with Fou's violin.