Fun Little Theme I Found [SPOILERS ALL]

So I’m currently reading through the Heroes, and I noticed something. Whenever an army is a main centerpiece, or characters are following in the wake of an army, mud is mentioned. I know it’s simply realistic that armies are going to leave mud as they march, but also the fact that “Back to the mud” is a common enough phrase, I thought it was sort of symbolic that such large machines of death would leave it in its wake.