Yurusen is a ghostly, floating cat-like creature who serves as a guide and mentor in the 'Kamen Rider Ghost' series. Often providing comic relief, Yurusen instructs Takeru Tenkuji (Kamen Rider Ghost) on how to use his powers and the Eyecons. Despite its sarcastic and sometimes condescending demeanor, Yurusen is a crucial ally, offering both advice and warnings, and helping the protagonist understand the spiritual world and his responsibilities as a Kamen Rider.