Sokichi Narumi is a key character in the series 'Kamen Rider W.' He is the mentor and father figure to the protagonist, Shotaro Hidari, and was the original Kamen Rider Skull. As a private detective in Fuuto City, Sokichi is known for his sharp wit, strong sense of justice, and cool demeanor. His legacy and teachings deeply influence the main characters, and his past actions play a crucial role in the development of the story and the emergence of Kamen Rider W.