Sieg is a major Imagin character in the tokusatsu series Kamen Rider Den-O. Known for his elegant and aristocratic demeanor, Sieg is a swan-themed Imagin who temporarily possesses the body of Ryotaro Nogami to become Den-O Wing Form. Unique among Imagin for his noble sense of justice and pride, Sieg plays a crucial role in assisting the Den-O team, often providing significant support during battles. His memorable catchphrase is 'My elegance will pierce the heavens.'