THE EMPTY EMPIRE (Kara no Teikoku), by Naoe Kita. First published in 1993 and first published in North America in 2006.
PLOT:
The Emperor Idea once ruled the world through a combination of incredible powers and indominatable charisma. Then the emperor suddenly died and the world was thrown into chaos. In the midst of this chaos, a stray duke and a whip-wielding girl from the streets find a boy that looks just like the late emperor. He's a rejected clone that was left without any memories and bearing a rose-shaped scar on his forehead. They bring him to the palace to teach the boy what he needs to know to survive, but there are many people who both adored and despised Idea and are determined to dispose of this doppelganger by any means.
