There were a lot of differences between HBO's Game of Thrones and what fans read in George R.R. Martin's A Song of Ice and Fire books, and with two more chapters still on the way, we can probably expect some significant deviations still ahead (even Martin has been waffling on just how close the infamous series finale is to his planned ending). Among the major changes from the page to the screen was the omission of fan-favorite zombie mama Lady Stoneheart, aka the resurrected Catelyn Stark (Michelle Fairley). Although Game of Thrones was not shy about bringing key characters back to life, and the number of undead only increased throughout the show's run, Lady Stoneheart never rose up to exact bloody revenge on those who betrayed the Starks at the Red Wedding. And now we know why.

In Entertainment Weekly's latest excerpt from James Hibberd's Fire Cannot Kill a Dragon, series co-creator David Benioff revealed the three reasons Lady Stoneheart never made it to the screen on Game of Thrones. The first was that he and fellow showrunner D.B. Weiss didn't want to spoil something that was coming in Martin's books, and the second is that they'd already been planning to off Jon Snow (Kit Harington) and bring him back to life, and they wanted the suspense to be at full-tilt for that event. 

"Too many resurrections start to diminish the impact of characters dying. We wanted to keep our powder dry for that," Benioff said.

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The third and final reason they declined to let Lady Stoneheart wreak havoc on the saboteurs who killed Catelyn and Robb Stark (Richard Madden) comes down to Fairley's performance in her final episode. Benioff and Weiss thought it was so powerful that they wanted to wrap the character with that and have it be remembered instead. 

That three-pronged explanation might not be the most satisfactory reasoning we've ever heard, but at least now we know. And let's face it, the eventual revenge we did get with Arya (Maisie Williams) and the Freys was still pretty delicious.

Fire Cannot Kill a Dragon hits shelves on Tuesday, Oct. 6. Game of Thrones is currently available to watch on HBO and HBO Max.  

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  Michelle Fairley, <em>Game of Thrones</em>  Michelle Fairley, Game of Thrones