Seiji Shinozaki is a protagonist of the fanfiction story The Dark Messenger. He is the father of Minato Shinozaki, and Sachiko Shinozaki, and the husband of Yoshie Shinozaki. He is the previous holder of Minato's, Wonder Deck, and is a off Shadow Rider. He was thought to be an antagonist, but was made into an anti-hero, after Sachiko's victory against Chazz. He is one of the three people to have ever defeated Minato in a Duel. The other two being Zane Truesdale, and Jesse Anderson (who was possessed by Yubel).