Captain Ken Vol 1

From the Digital Manga edition

Captain Ken is an enigma. Not a single person alive knows who he is, why he's on Mars, or why he looks just like Miss Ken Minakami. In a whirlwind of gunfights, horseback chases, and utter lawlessness, Captain Ken sparks a time of change. The townspeople seek to rid themselves of the corrupt Mayor Deven, and the Martians seek to reclaim the cities they were chased out of. Our valiant hero, while assisting every damsel in distress, loses sight of his own vendetta. Years after the Mars rush of the 21st century, the arrival of an honest man pursuing a vendetta sparks a revolution.

Source: Anime News Network Encyclopedia