The Japanese word for smoke is kemuri (煙).

Saohime had conspired with her elder brother Saohiko to murder the emperor and seize the throne. The conspiracy did not go unnoticed as the emperor ordered one of his generals to lead his army in pursuit of Saohime.

Once the army arrives at their castle, the general is perplexed by the amount of smoke covering the lands and castle. In the distance, he notices a glimpse of something that looks like an army of ghosts. The uncertainty of for which side the ghosts army is fighting, frightens him.

The treason of Saohime concerns the whole country. The death of the legitimate emperor could lead to chaos as clans would likely go to war with each other.

The ghost army represents the will of the people that have given their lives in order to unify Japan. The various spirits wouldn't allow Japan to fall back into another Sengoku period, which was a period of semi-permanent civil war.

The ghosts seem to have caused the conflagration at the castle of Saohime and her brother.

The general and his warriors were in pursuit to punish the treason of Saohime, but found that the penalty had already been given as they saw everything, including her, go up in smoke.