Sieg

"Advent! To the top!" - Sieg's catchphrase before fighting.

Sieg (ジーク Jīku) is one of the unofficial members of the Den-Liner, appearing in Kamen Rider Den-O. He owns the Wing Buckle and supports Ryoutarou Nogami the Wing Form. Sieg is voiced by Shin-Ichiro Miki, and his suit is portrayed by Naoki Nagase.

Sieg inside Ryoutarou's body will give him white hair strands with some feathers. His eyes will become white and glossy, and his clothes will have a feathery cape with white clothing. He is portrayed by Takeru Satou.