I don't have much inspiration to write any more, but reading Vathara's Embers makes things percolate in the back of my head. This is what eventually surfaced.
Times to Come
Shortly after she takes Ba Sing Se, Azula wakes in the middle of the night to the dark chill of someone standing over her. The man is tall, even for the Earth Kingdom, and slender, and there isn't enough light for her to pick out the color of his eyes. He doesn't feel like fire but of wind and lightning. So. Not the typical assassin, then.
And she can't move.
"I thought I should give the message in person," he says. He sounds almost like her father. And amused. He bends down and places a fat, upright cylindrical container on the lower half of her ribcage, just below her breasts and right over her diaphragm. The weight shouldn't be enough to make it harder to breathe, but it is. The man straightens and blends away into the shadows, and Azula feels her awareness expand and her ability to move return.
Nothing seems out of place in the quarters she's taken for herself, but Ty Lee is bound against the wall with braided coils of steel, spread-eagled, as if in preparation for flaying, her voice box carefully removed. Mai is nowhere to be seen.
Azula places her hands on either side of the container on her abdomen and lifts straight up, pulling the cover carefully away from the severed head on its tray underneath.
Her father stares back at her.
Then the sun rises and Azula wakes again; she rises with it and tells herself firmly that it was just a dream, even as she calls for a dragonhawk.
~ and miles to go before I sleep ~