“The Rains of Castamere” essentially serves as the Lannister family theme song. It represents the victory of Lord Tywin Lannister over House Reyne of Castamere in a war preceding the events of the show. Never heard of House Reyne? That’s because they were completely wiped out by the Lannisters, so the song serves as a warning to all who would dare defy the Lords of Casterly Rock. Here are the lyrics:
And who are you, the proud lord said, that I must bow so low?
Only a cat of a different coat, that's all the truth I know.
In a coat of gold or a coat of red, a lion still has claws,
And mine are long and sharp, my lord, as long and sharp as yours.
And so he spoke, and so he spoke, that Lord of Castamere,
But now the rains weep o'er his hall, with no one there to hear.
Yes now the rains weep o'er his hall, and not a soul to hear.
Then in Season 3, Thoros of Myr was singing it when Arya first encountered The Brotherhood Without Banners back in Episode 3. Does that mean The Brotherhood are in cahoots with the Lannisters? Or does it just mean that it’s a catchy song? Whatever the implications, we’re guessing episode nine has some trouble in store for the enemies of mighty House Lannister!