They are the vision of their parents, Uncle Edmure often teases, as much Lord and Lady Stark as Catelyn and Eddard once were.
The commons speak of Lady - a title that never fails to amuse them both - Arya, as cold as ice, unyielding, and relentless as winter's wrath. If Arya is the winter, Sansa likes to consider herself midday in late autumn. Arya shuns the pretenses and games a Lady must play, and is openly disdainful of the southern emissaries who often share their table, so it is Sansa who must warm the chill, turn ice to frost, and welcome their guests, dancing around their words like an oak's leaves might frolic in the wind.
Unity and peace are hard built; what little they have redeveloped has taken years. Even long after the wars have ended and the remaining Starks returned to Winterfell, there are those who contend the rights of the Queen in the North. Sansa cannot stop every battle, win every war, with words alone; it is then she turns to her companion and sister to lead. In the evenings when Arya returns home with her men, sword bloodied, eyes dark and hollow, she speaks not a word. Her younger sister spends those nights in the Godswood, but whether she prays to the Old Gods, the god of death, or their parents, Sansa will never know.
There is much Arya holds within, but her defenses are not impenetrable. When they rest together, deep in the night, Sansa often awakens as her sister dreams, vivid and violent, her legs and arms thrashing about until she looks ready to tear herself apart. The queen rouses her then, before the visions reach their peak, and holds her close, to offer what solace she can. Arya does not cry; she never cries. But Sansa does; Sansa cries the tears Arya refuses to let fall, until her throat is hoarse, her eyes are pink, and the sun peeks out on the horizon.
When they wake, Queen and Commander once again, armor mended, masks replaced, they break their fast with their adopted children - victims of the Game as truly as the Stark women - and start the day anew, as much a cycle as winter's end and spring's beginning.