The Heisei era of Kamen Rider has produced a number of highly popular series over the years, but of all the success stories there's one that truly stands out amongst the rest. First airing back in 2007, Kamen Rider Den-O not only spawned a 49 episode series, anime spinoffs, seven direct movies (four of which released under their own "New Den-O" banner), as well as prominence in significant crossover productions like OOO, Den-O, All Riders: Let's Go Kamen Riders and the first Super Hero Taisen. Its lead actor Takeru Satoh has gone on to have the most successful acting career of all the Heisei Kamen Riders, yet the popularity of the series allowed it to endure even when he was no longer able to continue to play the role. This of course made his surprise cameo in Heisei Generations FOREVER a particularly big deal. So what is it about Den-O that's made it so well loved? The series was written by tokusatsu veteran Yasuko Kobayashi (who's key writing works include Kamen Riders Ryuki, OOO and Amazons) and served as the eighth Heisei Kamen Rider series and 17th overall.