This article is about a/an spin-off media story in Kamen Rider Den-O.

April 3, 1971 (1971年4月3日 Sen Kyū Nana Ichi Nen Shigatsu Mikka) is the Kamen Rider Den-O Edition of S.I.C. Hero Saga, published in Monthly Hobby Japan magazine for Kamen Rider Den-O. Running from December 2008 to October 2009, the story expands upon the events of Climax Deka and Kamen Rider Nega Den-O's travel through time joining forces with the Great Leader of Shocker, with Den-O and Zeronos joining forces with the original Shōwa Kamen Riders to fight them. It features original characters Negataros Spirit Form (ネガタロス精神体 Negatarosu Seishintai) and Negataros's form as Great Leader Ganseki (岩石大首領 Ganseki Daishuryō).

Chapter titles
  1. Imagin Revival (復活のイマジン Fukkatsu no Imajin)
  2. Negataros Army (ネガタロス軍団 Negataros Gundan)
  3. Shocker Leader (ショッカー首領 Shokkā Shuryō)
  4. The Capture of Yuto Sakurai (囚われの桜井侑斗 Toraware no Sakurai Yūto)
  5. Five Plus One (5+1 Go Tasu Ichi)
  6. Comrade (仲間 Nakama)
  7. True Form (正体 Shōtai)
  8. Great Leader Ganseki (岩石大首領 Ganseki Daishuryō)
  9. Seven Riders (7人ライダー Shichinin Raidā)
  10. Ten Riders (10人ライダー Jūnin Raidā)
  11. From the Window of the DenLiner (デンライナーの車窓から Denrainā no Shasō kara)
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