I’m watching the new Shogun limited series. I’m in episode two, right at the beginning where the old emperor is dying and his son is asking how he will find him again. This gave me an interesting idea.
The villain is a raider. He travels from town to town, sacking and burning, killing everything in his wake. It turns out the raider is the rightful heir of a fallen house. The father of the main character from the “good” household tried to have the villain assassinated as a child to consolidate his own power. The boy’s parents were killed, but he survived. And when the boy’s mother/father lay dying, he asks how he will find them again. They say to light a candle and follow the smoke to the next world.
Grown into maturity, this concept has warped so that he believes the more smoke he creates, the easier it will be to find his parents. Thus he burns the lands of his enemy.