Shiro Unyuu is one of the two main characters in the Ukagaka (also known as Nanika) desktop mascot software. As the 'ghost' companion to the user, Shiro is known for her cheerful and curious personality. She interacts with the user through dialogues and offers various functionalities, such as reminders and weather updates. Shiro often appears with her partner, Sakura, and together they create a lighthearted and engaging experience. Her role is to entertain and assist users, making the desktop environment more lively and personal.