After an incident in one of the battles with a demon, Giyu received a wound and the demon's blood entered his bloodstream, which is why he turned into a demon. He lost his mind and had to be taken to Tamayo - a demon and a talented doctor who alleviated his condition, but still Giyu had to chain his right hand to the bed. His black hair was disheveled and not in his usual ponytail as his mouth was slightly open where his fangs were visible, while he letting out air. He was wearing a white kimono, and his blue eyes with narrowed pupils stared blankly at the ceiling, after the sedative that Tamayo gave him, he no longer tried to rush at anyone. Giyu could not speak clearly and only made quiet growling sounds in response to any questions due to his not fully restored sanity after turning into a demon, but after sedatives and treatment for a week, he seems to understand human speech more or less.