He may seem ironic at times, yet he always maintains an elegant demeanor. He cannot abide impulsive decisions. Highly ambitious and sensitive, he is easily startled or repulsed. He is hardworking and always carries out tasks meticulously, prioritizing the finer details. While very communicative, he prefers not to reveal his true feelings or thoughts; he also possesses a rebellious streak but manages to keep his aversion to following orders in check.

Having lived in Penacony since childhood alongside his father, he was trained to hone his skills in singing, telepathy, and the manipulation of Harmony. Although fiercely loyal to his Aeon, he never truly cared for rules and was often rebellious; he began his career with the Oak Family as an adult, fully dedicating himself to fulfilling his duties alongside his colleagues. While things seemed fine on the surface, he felt trapped in an unjust world manipulated by his own faction, leading to rebellious thoughts. He constantly heard voices and experienced hallucinations of his late mother, who had truly cared for and listened to him. Already strained by his work and family environment, he contemplated suicide, but before he could act, he was stopped by Sunday. At first, he viewed Sunday as an interloper and tried to keep his distance, but the more time they spent together, the closer they grew without him realizing it until Sunday became the only person with whom he could truly open up, transforming from a boss into a close friend. Ciel trusted him and sought his counsel, all while concealing his rebellious nature and deep longing for affection. Following the events in Penacony, he felt even more exhausted and betrayed by his own organization. Frustrated, he decided to board the Astral Express to take some time for himself. On one hand, he understood everything that had transpired; on the other, he could not accept that his superior had employed improper methods to achieve his goals yet he never harbored hatred toward him, feeling only a controlled frustration.