Hark! This article discusses the ending of Episode 2 of "House of the Dragon."

HBO's "House of the Dragon" ended last week's Season 2 premiere with one of the most emotionally brutal deaths ever in the "Game of Thrones" universe. Somehow "Dragon" managed to double the blow in Sunday's Episode 2.

That's right. Stoic identical twin knights Erryk and Arryk Cargyll (played by 34-year-old identical twin actors Elliott and Luke Tittensor) battle each other in a lethal, lookalike brother-on-brother brawl. It ends with both siblings dead.

The tragic fraternal fray between the Cargyll twins, Kingsguard members who went to opposing sides of the simmering "Dragon" civil war, is a "Thrones" legend – mentioned in reverential tones in author George R. R. Martin's source material. The "Dragon" screen realization of the legend lived up to the hype.

"This fight has been sung about," Elliott Tittensor tells USA TODAY. "So our battle really had to be epic."

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"I'd put our fight in the top two," Luke Tittensor adds, ranking the TV battle. "Top five for sure."

Here's what in Westeros happened:

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We've been waiting for this moment since the once inseparable twins split on "Dragon," with Arryk serving as King Aegon II's personal guard (the Greens) and Erryk serving as Queen Rhaenyra's personal protector (the Blacks).

After last week's murder of his son and heir, King Aegon (Tom Glynn-Carney) shrieks for revenge. His Kingsguard boss, Criston Cole (Fabien Frankel), shows his dark side devising the vengeful plan to kill opposing Queen Rhaenyra (Emma D'Arcy), who has been blamed for the crime. (Never mind that it was actually Daemon who orchestrated the killing.)

Cole, who breaks his Kingsguard oath of chastity regularly with Alicent Hightower (Olivia Cooke), hypocritically leans into the honor code to convince Arryk to take the odious task – sneak into the enemy's Dragonstone disguised as his well-placed twin, and kill Rhaenyra. Arryk burns Cole with his look but agrees.

"Arryk was forced to make the decision, and it's obviously a death mission," says Luke. "But Arryk's willing to fulfill that duty because all he's got is his honor, duty, and love for his brother."

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In George R. R. Martin's Targaryen family history "Fire & Blood," Arryk is discovered by Erryk in the Dragonstone, leading to the fateful battle. But on "Dragon," Arryk makes it all the way to Rhaenyra's chambers and brandishes his sword to the confused Queen, who thinks it's her guard. Erryk, tipped off about his brother's lethal presence, rushes into the room just in time. The sibling sword struggle is on.

The fight scene is almost entirely the Tittensor twins swinging long swords in full armor. "It was knackering," says Elliott. "That costume is hot in the best of times, never mind when you're swinging a sword. But we threw ourselves into it."

A stunt person was used only when Arryk gets thrown in the air landing on a vase. "I was glad that it wasn't me because my stunt guy hit that vase so hard he almost froze time," says Luke.

It's hard to tell, but Arryk is on the offensive most of the fight, with Erryk playing defense – not wanting to kill his brother but protecting his defenseless queen. When the final sword thrust reveals itself, it's Erryk sobbing and hugging the brother he's just run his sword through.

"You get to see the real human side of him pierce through," says Elliott, who was pleased to "show the world the connection we have as twins in the end."

With the assassin-brother dead, Erryk steps toward the still wary Queen before proclaiming, "Your grace, forgive me." To the shock and horror of all, the distraught knight impales himself on his sword. The legendary double tragedy is complete.

"The pain Erryk felt when he kills his brother is the most intense feeling he's ever felt," says Elliott. "When he says, 'Forgive me' he's saying it to Rhaenyra because he's about to sacrifice himself in front of her. But it's also directed towards his brother."

The fight is purposely confusing for onlookers and TV viewers, but not to Elliott and Luke, "The illusion is lost on both of us," says Luke.

The twins, born and raised in the northern English city of Manchester, appeared in Showtime's "Shameless" at age 11. They shared the role of Carl Gallagher for the first season before Luke left after being cast in the British soap "Emmerdale."

The major difference between the twins: Elliott has sleeves of tattoos, Luke has none. But in the Cargyll uniform, they are dead ringers.

"Dragon" creators took advantage of the likeness, swapping Cargyll twins in a crisis. In Season 1, Luke was rushed to set when Elliott couldn't do "Dragon" scenes due to a COVID-19 scare. "I woke up at 7 a.m. to 10 missed calls and thought this is not good," says Luke. "Stepping in on each other's characters is not something we'd do. But production definitely wanted it."

The twins have endured seasons' worth of understandable twin misidentifications.

"There were a lot of times when I'd be called onset and I'd look around and say, 'You actually need Luke for this scene, right? I'll go get him,'" says Elliott, laughing. "It happens to both of us. We're used to it by now."

On "Dragon," the two deaths in one assassination attempt will continue to rumble during the season.

"Things are going to get really messy," says Luke.

"The collateral damage and body bags are adding up, and the pressure is growing," adds Elliott. "Basically, there's no route back from here barring the death of pretty much everyone in the whole thing."