[GrandComplete]

Quote:

Originally Posted by Kamen Rider Die

My headcanon is that (like is sort-of established in Fourze) all of the Showa Riders are urban legends, and that Kaido is a huge nerd about them. As a kid growing up, he got obsessed with stories of Kamen Riders. He internalized all of that iconography, so when he had to be a hero to that orphan, his go-to was Ichigo. (Also, Yuuji and Yuka are thoroughly sick of him talking about Riderman.)

Another fun little theory is the idea that Smart Brain is just simply another evil organization controlled by the Great Leader. And being honest here I think Kaido knowing the Ichigo pose is Inoue paying respect to his dad. Masaru Igami a prolific writer for Showa Kamen Rider.