Sengoku

Sengoku was released in arcades in 1991 by SNK on their Neo Geo hardware. It is a scrolling beat 'em up where you play a modern ninja (or cowboy) in a post-apocalyptic city fighting demons frome feudal japan.

Story
400 years ago, there was a warlord who loved destruction. 2 Samurai decided to go against him. They defeated him. The warlord left a prophecy before he died.... "I shall return in 400 years! The madman and I will work together to rule the world!" 400 years later, the prophecy came true.