Kamen Rider Build Season 1 Episode 23 The Phantom of the West ( Air Date 2018-02-18 ) Genre Action & Adventure, War & Politics, Sci-Fi & Fantasy, Drama, Kids category. Overview "Taking advantage of the conflict, Seito invades and conquers Hokuto. Now bent on seizing all of Japan, the Seito forces invade Touto, led by the mysterious Kamen Rider Rogue.".