I make it no secret that I am not the biggest fan of Fire & Blood. It's by far the weakest of GRRMs work and honestly the majority of the changes in House of the Dragon have been for the better. There are quite a lot of perplexing writing decisions in the book, and I think, if the trailers are not misleading, that the show has actually resolved one of the biggest and honestly weakest bits of writing for the Dance in the book. Again, spoilers for season 3 of House of the Dragon.
In the book, Aemond is laser-focused on Harrenhal and Daemon to the point his brain falls out. He makes no effort to really take any precautions for King's Landing. No attempt to recruit Helaena to battle, no attempt to make sure its defended. The idea that Rhaenyra might use her dragons to take it is not even thought of by him. As if that's not bad enough, he then spends 19 days marching with Criston Cole, riding ahead of the column on Vhagar. That's 19 days of leaving the city undefended. Plus however many days he dicks around at Harrenhal celebrating his "victory."
He is so inept he practically holds the idiot ball and delivers King's Landing to Rhaenyra on a silver platter. It's one thing to think Daemon is the bigger threat, but it is quite another to literally just do things to make the Blacks war efforts go smoother. There's a lot of foolhardy and glory-seeking buffoonery in this series, but personally speaking I enjoy characters in the fiction I consume to actually, you know, be intelligent and not braindead.
In the show, Aemond is still kind of a fool and a moron, but he's actually a lot more proactive, methodical, and careful about his actions. He sends Criston ahead of him, which does leave him vulnerable to potential attack by Caraxes but also means he stays at King's Landing and keeps Vhagar around to deter any outright attacks by the Blacks. And when the dragonseeds claim new dragons, he makes the effort to try and recruit Helaena to fight on Dreamfyre. Already, I view this as a considerable improvement as it actually bothers to have the characters try to take into account the possible ways their plans may fail, to show that they are thinking people trying to strategize and adapt to ever-changing situations.
Once Aemond reaches Harrenhal in the book, it is empty. There is nobody there. Just Simon Strong's family. Not even an army. And instead of going "huh, that's weird, Daemon was definitely here so where did he go?" Aemond just thinks "oh... well I guess this means I win," and then starts partying to celebrate what a great job he's done finding an abandoned castle and not finding his ultimate rival anywhere and finds absolutely nothing suspicious about this.
The trailers for season 3 however show that something very different goes down when Aemond arrives at Harrenhal.
Harrenhal can't catch a damn break. Dragons just keep fucking burning it.
Me when I'm aurafarming like a shounen antagonist.
RIP Simon Strong, I'll miss you :c
Aemond arrives at Harrenhal with fire and blood, no holds barred, burning shit and cutting people down eagerly. Considerably different from the book. We also have shots of Daemon fighting in the Red Keep so I wonder if they'll cut between the two of them taking each castle. It'd fit pretty well. And though this would be a show-only battle, I don't think this is solely for providing more action for the series.
It's actually really fascinating as a thematic parallel between Daemon and Aemond. Both men have fearsome reputations as very hot-tempered, fiery, dangerous warriors. However, despite this, Daemon actually manages to take Harrenhal bloodlessly. At most, he kinda just knocks one guy out, but he doesn't burn anything, nor does he slaughter anyone. Meanwhile, Aemond fully indulges in violence to burn the castle and massacre the garrison inside of it. The book kind of has this as well, since Daemon also takes Harrenhal without casualties and shows mercy while Aemond massacres the Strongs to a man. The show is merely making this contrast all the more noticeable than the book.
I also think leading to more of a battle at Harrenhal fits as a better climax than the book. The show spends a lot of time building up Aemond's approach to Harrenhal and Daemon building his army at Harrenhal. Far more than the book. The climax of this in the book is an anti-climax done in a spectacularly incompetent fashion that makes for quite honestly a very boring story. Here, the show is genuinely building up to an explosive climax at Harrenhal, even if, like the book, Aemond is not going to find Daemon there.
But that isn't the most interesting part of this for me. In the trailer we also see Alicent warning Aemond:
"Rhaenyra is coming. It is no longer safe here."
And she is later seen trying to escape the city with Helaena. At this point, Aemond is very well aware that Rhaenyra is almost certainly going to try to take King's Landing when he takes Harrenhal. It's mentioned too many times for him to really ignore. And since this is after the Gullet and Jacaerys's death, Alicent is almost certainly convinced that Rhaenyra will not be kind when she comes to take the throne.
Here is my prediction: what Daemon does to Aemond at Harrenhal, Aemond does to Rhaenyra at King's Landing. Let me explain.
Daemon purposefully leaves Harrenhal so that Aemond goes there to find he has wasted his time and in that time he helps Rhaenyra take King's Landing. He essentially sacrifices Harrenhal to take King's Landing, the bigger prize. Meanwhile, I think Aemond purposefully leaves King's Landing so that Rhaenyra can take it while he defeats Daemon at Harrenhal. In other words, sacrifices King's Landing to get rid of Rhaenyra's most competent supporter. Both men believe they are sacrificing something to gain an even greater strategic victory against the other.
Of course, this works out better for Daemon than Aemond, but it suddenly makes the two prince's rivalry that much more compelling. If I'm right, then the show has taken an aspect of the book that has always bothered me as sloppy and poorly handled and actually made it a more interesting, compelling back-and-forth game of strategy with more of a climax. I'm also fairly excited to see what Aemond does after this, since he kind of disappears and does nothing before committing genocide in the Riverlands. That simply isn't going to be the case in the show, so I'm looking forward to see what he does exactly, especially with Alys Rivers.