Has it ever been confirmed what name Elia Martell said before she died?
“A council seat is not to be despised,” Varys admitted, “yet will it be enough to make a proud man forget his sister’s murder?”
“Why forget?” Tyrion smiled. “I’ve promised to deliver his sister’s killers, alive or dead, as he prefers. After the war is done, to be sure.”
Varys gave him a shrewd look. “My little birds tell me that Princess Elia cried a … certain name … when they came for her.”
“Is a secret still a secret if everyone knows it?” In Casterly Rock, it was common knowledge that Gregor Clegane had killed Elia and her babe. They said he had raped the princess with her son’s blood and brains still on his hands.
“This secret is your lord father’s sworn man.”
“My father would be the first to tell you that fifty thousand Dornishmen are worth one rabid dog.”
Varys stroked a powdered cheek. “And if Prince Doran demands the blood of the lord who gave the command as well as the knight who did the deed …”
On face, it seems like the answer is Gregor Clegane - that’s certainly what Tyrion seems to believe - but Varys keeps hinting not so subtly to the participation of Tywin Lannister in Elia’s murder. To what extent Elia would have even known Gregor is speculative at best - she might have been present for Rhaegar’s knighting of Gregor (itself a confusing affair), but she definitely had every reason to know Tywin Lannister. She had met him personally, after all, may have been with Oberyn for her mother’s deathbed confession of Tywin’s brusque refusal of Elia for Jaime or Cersei for Oberyn, and his reputation would have preceded him by the time she came to court. She also married Rhaegar, and while Elia might not have been aware of Tywin’s full machinations to make Cersei the crown princess, it would not have required too complex an analysis to conclude that she, Elia, had beaten Cersei Lannister for the greatest marital prize in Westeros. So when Elia was told that Gregor and Amory were scaling the Red Keep, I can see where she might have cried Tywin’s name. It would have been a moment of horrific realization, where all the pieces came together in her mind: she had taken what Tywin wanted; Tywin was absolute in his brutality when it came to those that wronged him (as his own propaganda proclaimed); Tywin’s men were coming to kill her.