Spoiler alert! The following contains all the attempted fratricide details of "House of the Dragon," Episode 4.

When there's a major dragon battle to be fought in HBO's "House of the Dragon," you can bet that eye patch-wearing Prince Aemond (Ewan Mitchell) and his scaly steed Vhagar are in the mix. The deadly rider-dragon duo already lit fire to the strife between the Greens and the Blacks by ripping Prince Lucerys and his dragon Syrax out of the sky in the Season 1 finale.

Sunday's Episode 4 (now streaming on Max) moves the civil war to widescale bloodshed and the series' biggest dragon clash at the Battle at Rook's Rest, a stronghold for the Queen Rhaenyra-supporting Blacks.

Greens commander Ser Criston Cole's (Fabien Frankel) seemingly foolhardy attack on Rook's Rest walls is a ploy to draw out Princess Rhaenys Targaryen (Eve Best), who flies out to protect the vital castle. Hidden Aemond and Vhagar are about to execute a secret Rhaenys ambush when, lo and behold, drunken and glory-seeking Greens King Aegon (Tom Glynn-Carney) flies his Balerion into the fray.

Concealed Aemond calmly waits for Aegon and Rhaenys to engage before flying on a double dastardly ride — first dragon-knocking his own brother and king out of the sky (whoops!), then somehow hiding Vhagar behind Rook's Rest to take out unsuspecting Rhaenys.

Need a break? Play the USA TODAY Daily Crossword Puzzle.

Nooooo! Multifold tragedies befall the Blacks as Rhaenys falls like Hans Gruber, dying hard along with monstrous Meleys right on Rook's Rest — the walls the princess was valiantly trying to defend. Ironically, the giant-dragon-sized breach allows The Greens' foot soldiers to enter victoriously. Nice work, Aemond.

"Aemond and Vhagar are a power couple," Mitchell tells USA TODAY. "They're there to shock the audience, it's in their DNA. Aemond recognizes (that) what he does in the skies above Rook's Rest changes things forever."

"Dragon" standout Mitchell, 27, breaks down the episode.

Question: Can you draw a line from Episode 3, when mocking King Aegon humiliates his warrior brother Aemond cuddling a madam in the brothel, to Aemond striking back in Episode 4?

Ewan Mitchell: Aemond is humiliated by his brother in the brothel during Episode 3. The moment takes him back to being a young boy, neglected, bullied and tormented relentlessly by his brother. His safe space is violated in the brothel; it's the most vulnerable you'll ever see Aemond. Weakness is not a word in Aemond's vocabulary. I love Robert De Niro's line in "Heat" — "Don't let yourself get too attached to (anything) you're not willing to walk out on in 30 seconds flat if you feel the heat around the corner." Aemond has a very similar code. And that code comes into play, that switch goes on. Aemond is easily able to get up and walk away from the madam in that scene.

But Aemond walks away stark naked, which is more a power exit than Robert De Niro made in "Heat." Why that decision?

It was a long conversation with me, director Geeta Patel and executive producer Ryan Condal. Aemond is a kid who does not care what you think about him. We discussed grabbing a blanket or using his hands to cover himself. But Aemond shows he can stand up there without any armor or brandishing a Valyrian steel sword. He just walks out.

Aemond references the brothel episode in the Episode 4 Council meeting by saying Aegon was too "occupied" to learn of his secret war plan with Criston Cole. Aemond totally dominates his brother in the meeting in English before switching the language to High Valyrian. How did you pull that off?

I have trouble rolling my "r's" in High Valyrian. But that turned out interesting since Aemond doesn't flower up this beautiful language. He uses the language more lethally. The Council meeting is very much a public shaming, but switching to High Valyrian allows Aegon to save face, since only the two brothers understand it. It allows Aegon to recover.

Is the Battle at Rook's Rest Aemond's big chance to make his move?

In the first two episodes of Season 2, Aemond operates from the peripheries. He has a shadow council with the like-minded Criston Cole. They lie dormant and wait for their moment. Then, when Aemond sees Aegon fly overhead at Rook's Rest, he just sits back a little longer. Maybe Rhaenys will take out Aegon, or Aegon might get lucky and take out Rhaenys. Aemond sees the whole game board before flying.

Aemond totally takes out his brother intentionally when he has the chance.

It's certainly intentional, even if it does raise the question of whether Aegon was just in the way. But Aemond never would have planned to hurt his brother. Aegon was the variable in the situation. So two dragons with one stone, taking two players off the game board for Aemond.

In the last scene, Aemond shows no remorse after seeing his lifeless brother surrounded by a smoldering dead dragon. That's his doing. Before Cole interrupts, is Aemond about to go over and make sure his brother is dead with his sword?

That might be the intent for sure. Or maybe he's just sheathing his sword. You don't know what Aemond's purpose is. Either he's checking on his brother or finishing him off. That ambiguity is super interesting. If I answer the question, people will stop asking questions. What I love about Aemond is he always keeps you guessing.