I'm sorry I don't want to be rude 😅 but, Jyamashin is his final form, this has already been confirmed several times, but I it don't take away from how special and spectacular Plosion Rage is.
Quaternary rider movie forms - kamen rider zangetzu fourze arms - kamen rider zangetzu WM arms - kamen rider lazer chambara gamer - kamen rider imperial demons - kamen rider buffa plosion rage