So today I watched Blade 17. I noticed that they made a specific point of having the counter go down when Leangle used his cards, which persisted throughout the episode. They also referred to Leangle as a "Kamen Rider" specifically in the show, which was cool
This also was the episode where Kenzaki imagines himself getting arrested for shoplifting and then promptly apologizing to the lady (isn't the store owner also in Ryukendo?)
I might have skipped a disc, but this seems like the first episode which really introduces Leangle, Mutsuki, and with Kiryuu, as well as the concept of the Remote Card