|Age:||Unknown, Appears 16 (O5)|
Yuki has a very stoic and introverted personality, preferring simple body language rather than speaking. When prompted to speak, she does so in a very concise manner, always speaking in a monotone and displaying a dispassionate complexion. She thinks very rationally, and finds it difficult to communicate with normal humans due to her intelligence and lack of empathy. She enjoys reading, and is seen reading a book in the majority of her appearances, typically of the science fiction or mystery genres. As the series continues, she develops a sense of humor, although her unchanging facial expressions make it near-impossible to discern whether she is joking or not. Despite her reserved manner, she is reliable and trustworthy, resulting in Kyon trusting her more than other members of the SOS Brigade.