During a fight in the World of Black RX, Apollo Geist of Dai-Shocker escaped into another dimension with Decade in pursuit. Arriving at the other end, Decade found a Kotaro Minami who transformed into Kamen Rider Black to attack him RX! Dai-Shocker Attack until Diend arrived and summoned Femme to hold him off. The next day, after learning that he was in the World of Black and seeing that he was on his own in saving Natsumi, Decade ambushed Guy as Ryuki and fought him until he used a little girl as his hostage. When Decade took a hit from Diend to save the child, Black watched and had second thoughts about him as Apollo Geist escaped. After explaining that Apollo Geist came to the world before and recruited the cult Gorgom into Dai-Shocker, Kotaro revealed that Joe the Haze ended up in his