Kamen Rider Black RX: Run All Over the World (1989)

The story begins on a U.S. Platoon Army Base. Crisis Empire sent some soldiers there, which was a trap for Minami Kotaro (Black RX). Kotaro fights the 3 Skull Monsters (from the first 2 eps of Kamen Rider Black RX) and is sent back through time. Kotaro meets up with some more old enemies, specifically, the Golgom Priests! Kotaro, being back in time, became Black again! Black trying to survive is captured. BUT since Kotaro time traveled, his persona split up! Black RX came to save himself (Black). Later, Robo Rider (also Kotaro) shows up. And then, Bio Rider (who happens to be Kotaro as well). They join together to fight the Crisis Empire.