At the auditions for Agito. One of the finalists of the title role was Yuusuke Kousaka. He's the son of Ryo Hayami, AKA, Kamen Rider X. Toei had a policy for main actors family members not to be involved in front of the camera in a key role, possibly to avoid cases of nepotism. Eventually, his family history was unearthed and Kousaka was disqualified from from the auditions.
The word "Agito" is Latin for "keep going", "move", fitting the theme of endless evolution of the titular Kamen Rider and the show itself.
Agito is the first Kamen Rider series to feature the three main types of Riders: a mystical Rider (one that draws power from ancient technology or mystical methods), an organic Rider (one whose anatomy changes to become a Rider), and a high-technology Rider (one who is either a cyborg or uses advanced technology to fight).
This is the first Rider series with a "speaking device", in the form of G3-X's GX-05 Kerberos. This would begin a significant usage of speaking devices within Kamen Rider; all of the Visors of the Riders in Kamen Rider Ryuki would likewise speak, while the Drivers of Kamen Rider 555 would be the first transformation device to speak.
This is the last series that is associated with Nippon Music Group. From Kamen Rider Ryuki onwards, Avex Entertaiment became the new music label for Kamen Rider Series.