Brought on by popularity for the series, this DVD Special feats. two half-hour side stories that take place during the events of the show. Both stories appear to take place just after episode 20, the first episode of the Helheim Saga. The Kamen Rider Zangetsu side story begins with Takatora telling Kota about the truth behind Helheim. While a childhood friend pays Takatora a visit, a mysterious Kamen Rider that has control over cracks begins to hunt down Yggdrasill’s forces. The Kamen Rider Baron side story begins with Kaito seeking out the Overlords for Professor Ryoma. A prince visits Zawame and when he finds out that Kaito looks exactly like him, he decides to forcefully switch lives, resulting in conflict.

An accident during tests of an anti-plasma artificial magnetic shield at Japan's Ground Self Defense Force East Fuji practice range sends the 3rd Special Experimental Company, under Colonel Matoba on a time-slip 460 years into the past, into 'the Age of civil War'. At the same time an imaginary-number anomaly thought to be caused by interference from the past begins eroding the present.