One of the things I miss from the books of the A Song of Ice and Fire series while watching Game of Thrones is how much denser the stories are in the books. This is occasionally frustrating, I don’t actually need to know how every character breaks their fast for example, but a rich, multi-layered world offers a lot more in the way of context and depth. We are not just reading a story about our central characters, we are reading a story about a WORLD and all the people in it. The narrow focus of television certainly helps clarify certain stories or condense them to their salient points, but it also leaves out a bit of the extra flavor.
But sometimes, if you pay attention, you can get a bit of it going on in the background. As we finish season six and look towards the final 13 episodes of the show, it’s worth noting that several important houses have been almost or entirely eliminated. As Daenerys sails towards Westeros with a fleet made up of allies foreign and domestic, there are more than a few spots ripe for the taking. As far as the show* is concerned, all the following castles are completely undefended:
Storms End and Dragonstone: Both former seats of the Baratheons. The entire legitimate Baratheon line has been extinguished and unless Gendry shows up with the worlds most massive forearms and sudden divine understanding of his parentage, that’s not likely to change. Even if he did, he’d have to pick one castle, leaving the other undefended. It will be interesting to see how the remaining houses of the Storm Lands side when Dany arrives: with Robert Baratheon’s widow or with the daughter of the man he rebelled against?
The Dreadfort, Karhold, and Last Hearth: The Bolton line has been eliminated, Smalljon was last seen on the bad end of a neck-biting and face-stabbing by Tormund, and as far as I know there’s not been hide nor hair of the young Lord Karstark seen since the Battle of the Bastards. Last Hearth in particular is important, as it’s the last castle south of The Wall.
The Eyrie and Harrenhal: Littlefinger is at Winterfell with the Knights of the Vale, technically the Eyrie and his own castle Harrenhal are without protection. I doubt Harrenhal needs it, since it’s protected by its own curse, but interesting that the young Lord of the Vale appears to have been left alone without his army or Yohn Royce to protect him.
Casterly Rock: Jaime has the entire Lannister army back in King’s Landing. Kevan and Lancel were killed in the sept. Who’s holding down the fort over in the West? Who knows.
And, while they’re not quite undefended, I would say that The Twins and Riverrun are both pretty questionable as far as defenses go. There are two types of disasters that can befall lines of succession: no more heirs, and too many heirs. Most of these castles are suffering from the first. Both The Twins and Riverrun, with the death of Walder Frey, are suffering from the second. Given what we’ve seen of the Freys so far, it seems unlikely that they will be able to hold off on petty infighting in order to mount a proper defense of either castle.
So when Daenerys arrives triumphantly in Westeros and finally at least two or three timelines have to line up with each other, there are plenty of places that she can grab easily and quickly in order to mount a better offense on King’s Landing or other valuable targets. Especially now that Winter has arrived, any castles that have a store of grain in them already would be especially important. And any new ruler is obligated to reward their loyal subjects, by bestowing titles and lands upon them. Dany would be able to do so without depriving any existing Westerosi families of their ancestral homes.
There are two wars to come in the next two seasons: the final war for the Iron Throne, and the War for the Dawn or the war against the White Walkers. These castles will be very important to both wars, and it will be interesting to see how they are handled next season.
*The books tend to feature far more extensive family trees, so there are many families that have been eliminated on the show that are still fine in the books. But some of these castles are without a Lord or Lady in both.