From the Project Sekai wiki:

Shiho is introverted and dislikes interacting with others. She immerses herself in her hobbies and doesn't care what other people think about her. Although she is introverted, she is not unkind, and is usually willing to help others. She is a straightforward person and speaks bluntly. Her cold, detached demeanor comes from her fear of hurting and dragging down those around her. Because of her aloof persona, rumors about her have previously spread throughout school, most of which claiming her to be a bully.