This post contains spoilers for Game of Thrones Season 7, episode 1, titled "Dragonstone," as well as plot points from George R. R. Martin's books.
Even if you've never read George R. R. Martin's A Song of Ice and Fire novels, chances are you're familiar with the name Lady Stoneheart — if only from hearing your disgruntled book-reading friends complaining about all the deviations that HBO's Game of Thrones has made from Martin's storylines.
In the book series, Lady Stoneheart is the reanimated corpse of Catelyn Stark, resurrected by Beric Dondarrion through the power of the Lord of Light. After being dumped in the river by the Freys following her murder, she's almost unrecognizable, only able to speak by covering the slit in her throat. Following the Red Wedding, she's consumed by a thirst for vengeance, and kills any Frey, Bolton or Lannister she comes across as payback. Read more...More about Game Of Thrones, Arya Stark, Lady Stoneheart, Game Of Thrones Season 7, and Game Of Thrones Recap