Sieg (ジーク, Jīku) is a major character in Kamen Rider Zeztz. He is a criminal and terrorist who was recruited into CODE as an agent known as Code Number: One (コードナンバー：ワン, Kōdo Nanbā: Wan) before he was dismissed for fusing with the Punish Gore Nightmare. Having resurfaced as Kamen Rider Dawn (仮面ライダードォーン, Kamen Raidā Doōn), he was an enemy to Zeztz until his separation from Punish and self-redemption.