-The "Nega World" is not really Natsumi's home dimension- it is in fact a copy-world that Narutaki has trapped Decade and co. in, in an attempt to stop them. The "Nega" not only refers to the dark riders, but the term "negative" as in film
-Decade's episode number of 30 has been extended to 31, because RX World's two episodes were originally supposed to be just one
-Decade's 3-part finale (29, 30 and 31), will feature the return of some of the hesei actors:
Suga Takamasa (Kidou Shinji/Kamen Rider Ryuki)
Matsuda Satoshi (Akiyama Ren/Kamen Rider Knight)
Handa Kento (Inui Takumi/Kamen Rider Faiz)
Morimoto Ryouji (Aikawa Hajime/Kamen Rider Chalice)
Keisuke Kato (Nago Keisuke/Kamen Rider Ixa)
Yamamoto Shouma (Nobori Taiga/Kamen Rider Saga)
-A rumored "KW" will also appear in the final three episodes. It has been theorized this is either Kurenai Wataru/Kamen Rider Kiva, or Kamen Rider W.