Ikurō Hoshi is a young man in his mid-twenties who works at the Hotel Inhumans, having been employed there for approximately one year. His physical appearance is distinctive, featuring slightly drooping brown eyes and brown hair that he typically wears swept back from his face, with a single strand left hanging as a fringe. For his professional duties, he dresses in suspenders without a jacket. In contrast, during his days off or in private settings, he adopts a much more relaxed look, letting his hair down and wearing simple, plain clothing such as a hoodie. He also has a notable habit of putting on glasses when he wants to question or pressure someone, using them as a tool to increase his authority in a situation.

Personality-wise, Hoshi is an independent individual who lives alone and manages his own life. He possesses a range of personal interests and talents, including a love for listening to music, cooking, and playing the piano. At the beginning of the series narrative, Hoshi repeatedly expressed strong feelings of aversion and distrust toward assassins. However, as the story progresses and he witnesses the lifestyles and codes of the killers around him, his perspective begins to shift significantly.

Within the story, Hoshi serves as a concierge at the hotel, but his role extends far beyond typical front desk duties. He is also specifically responsible for gathering information, a task that takes him to various parts of the hotel. He frequently provides services directly to guests in locations away from the reception desk, such as in their private rooms.

Hoshi's motivation to work at the Hotel Inhumans is rooted in a tragic personal history. Shortly before his twentieth birthday, his mother was murdered by a mysterious individual, and Hoshi himself was nearly killed in the same incident. He was rescued by the Hotel Inhumans at that critical moment. In order to uncover the truth behind his mother's death, he actively requested to be hired by Sara Haizaki. At that time, he was still using his family name at birth, Sorashima, but he later adopted his mother's maiden name, Hoshi.

Throughout the series, Hoshi undergoes notable character development. His initial, deep-seated distrust of assassins and killers is a core part of his early demeanor. Yet, by observing and interacting with them, his feelings begin to change as he gains a better understanding of their ways of life. His notable abilities include his skills in information gathering and analysis, which are central to his job, as well as his proficiency in playing the piano and cooking in his personal life. His tendency to wear glasses during interrogations also highlights a more strategic side to his personality.