"and what of my wrath"
Cersei’s “And what of my wrath, Lord Stark?” in AGoT is one of my favorite lines in the series and is easily tied for first as my favorite Cersei line with “and hair grows back”.
And I was thinking about it and I realized that “And what of my wrath?” is kind of another way of saying the words of the House Cersei is supposed to belong to–Baratheon. The idea of owning and utilizing one’s anger–OURS is the FURY, what of MY WRATH–is basically the crux of both phrases. Even the words of Cersei’s own House–Hear Me Roar–are a “DON’T FUCK WITH ME” warning akin to “ours is the fury” and “what of my wrath”.
This line follows Ned warning her that “Robert’s wrath will follow you wherever you go” or something along those lines, so Ned is expecting very Baratheon-ish behavior from Robert. Even though Cersei is married to him, she’s still very fully Lannister, and I think Ned views her only that way. I think he views her (and rightly so, a lot of the time) as a Tywin-type, a person of cold cruelty and silent anger that are dangerous in their own way.
During this scene, Robert is off hunting already; he is falling to Cersei’s wrath as she and Ned speak. With his death Cersei becomes even more powerful. The same way Robert’s rage over Lyanna being “stolen from him” and subsequent fierce hatred for Rhaegar and the Targaryens led him to war and then won him the throne of Westeros, Cersei’s has done the same. She took the words of his House when she married him and used the strategy they suggest to take the throne just as he did. Cersei is full Lannister, but in this scene, in this moment, she is saying to Ned that she’s been married to his awful friend for half her life and that she has learned the lesson of House Baratheon. In this scene Cersei tells Ned almost explicitly what she has done, with just those five words. From her hatred of Robert, from her rage over the disgusting way he treated her, Cersei has utilized her fury to become powerful.