Kamen Rider Black RX's ending

I was really oftput by intro of R/X, as it really didn't seem to fit Minami Kotaro's character.

Then again a comical Minami Kotaro gave the actor a lot more acting to do. He wasn't quite the it's Golgom's fault trope, but he didn't really do much in the show.

So I skip to the ending and am pleasantly surprised.

I don't even know if Amazon is canon to his actual character, but at least it's more of the idea of Amazon than the actual canon of the character, something Decade fans have forgotten.

So anyway, Jak is defeated after being stabbed in the eye, despite R/X stating he was manipulated by Crisis Emperor.

The Crisis Emperor in the end attempts to enlist R/X as a member of Crisis to prevent a loss of Earth. M denies this after Jak's defeat and then attempts to kill R/X only for Crisis Emperor to stop her, if you know what I mean. Then R/X meets D, who reveals that Demon World was actually a duplicate Earth suffering from the Earth's pollution. Later the Crisis Emperor, who states that even if Crisis is defeated, they will reemerge and fights R/X, who states that it is Crisis' corruption

So the ending is actually very sad for multiple reasons and interpretations.

1) it's not revealed whether Crisis comes back or not.

2) it is the end of the Shotaro Ishinomori era of Kamen Rider, which who knew was going to happen then.

3) This gets adapted into Saban's Masked Rider.

4) Pollution from Earth destroys Demon World because R/X defeats Crisis Emperor. What happens to Earth then?