Kazuki Namioka (波岡 一喜 Namioka Kazuki) is a Japanese actor. In Kamen Rider Series, he played Yū Yamagoshi in episodes 3 and 4 of Kamen Rider Den-O. In the 2004 Toho series, Genseishin JustirisersImage:Icon-crosswiki.png, he played Shiro Jinno/Demon KnightImage:Icon-crosswiki.png; as well as Shishimaru in the 2006 tokusatsu Lion-Maru G. He later played Lock Dealer Sid/Kamen Rider Sigurd in Kamen Rider Gaim. He celebrated his 35th birthday while filming for Gaim's third episode.