Kamen Rider Wizard has the belt you have to shake hands with, it's almost like the whole series was a lesson in manners. Check the center of his staff weapon. Same handshake icons!
As to what Kamen Rider is, every Kamen Rider is different, the first was a normal teen kidnapped and cybernetically enhanced but something happened to prevent the brain wipe part of the procedure, so instead of their most powerful weapon, he became their most powerful enemy!
Since then, though, origins have varied from being the last to believe in magic, to finding a train pass some girl dropped, to being really good at videogames!