Kamen Rider Black RX (1988)

While RX is a lighter show it is still the direct sequel to black so if you want to see the next part of the story for our Kamen rider watch RX

Both feature villainous organizations where the higher ups constantly argue and one up eachother. In RX they do sever a leader while in jetman they are all trying to become the top dog

Kuuga is technically the series after Black RX so if you want to watch the Kamen Rider series in order then watch Kuuga after Black RX.

Half a year after the downfall of Gorgom, Kotaro Minami has gotten a job of a helicopter pilot in a business owned by the Sahara family. Kotaro is later captured by the Crisis Empire and offered a place in their group. When Kotaro refused, his King Stone was shattered and he was thrown into space where the sun's radiation mutated his King Stone and he mutated into Kamen Rider Black RX. With his new powers, he battles the Crisis Empire and thwarts their plans to take over Earth.