Discuss what to use Alayne for

The three of them were alone in the solar (doors barred, fire high, the rest of Winterfell shut out beyond thick stone).

Near the hearth, hands clasped and utterly still, Alayne waited in perfect silence, black hair spilling over one shoulder like spilled ink. Obedience was her native language now; she had no need for any other.

Jon leaned against the edge of the table, arms folded, watching Sansa with that new, unreadable stillness.

Sansa circled once, slowly, the way a wolf circles a prize it has already decided to keep..

“She is magnificent,” Sansa said, almost to herself. “Taller. Stronger. More… everything.”

She paused behind Alayne, lifted a strand of that midnight hair, frowned faintly.

“Only the hair breaks the illusion,” she murmured. “Black is striking, but it must be Stark auburn if she is to be my perfect double.”

Jon spoke without moving, voice low and certain. “Alayne’s hair is auburn (rich, dark, the exact shade of yours and our mother’s). It always has been. No one will ever notice otherwise unless we wish it.”

The words settled over the room like warm snow. The black strands shimmered, lightened, caught firelight in a sudden blaze of deep red-gold. In a single heartbeat it was auburn (thick, gleaming, unmistakably Stark), falling to the small of Alayne’s back.

Sansa’s breath caught in delighted laughter. She threaded her fingers through the new color as though it had always been there.

“Much better,” she whispered.

She stepped to Jon’s side, shoulder brushing his.

“Listen,” she said, eyes bright. “From now on she walks ahead of me (always ahead). Half a head taller, auburn-haired, face colder than mine. The lords will see two of us and never be certain which one to fear. When I need to be in two places, she will be the one they see. When I wish a man to feel small, she will stand at my left and look down at him. When I wish them terrified…”

Sansa’s smile turned sharp enough to cut. “They will remember the last man who tried to own this face now wears it and kneels.”

Jon’s mouth curved, the smallest acknowledgment.

“Body double,” he said. “Displayed, not hidden.”

Sansa laughed aloud (a bright, giddy sound that belonged to a girl who had just been handed the world on a silver platter).

“Exactly. They will write songs about the twin Lady Starks of Winterfell and never know which one holds the knife.”

She turned back to Alayne, voice dropping to silk over steel.

“One final rule,” she said. “Whenever you stand in my place (hall, yard, or council), you will speak with my words alone. If I hand you a letter, you read it. If I whisper a sentence, that sentence is all you say. You may smile, you may glare, you may let them drown in those eyes, but the voice they hear will always be mine.”

Alayne sank to one knee, Black hair spilling forward.

“As my lady commands,” she answered, and the cadence, the lilt, the faint northern crispness were already Sansa’s own.

Sansa reached down and brushed a knuckle along Alayne’s cheek, tender and possessive.

“Good girl,” she said softly. “Rise. From this morning on, the North will never be sure which Sansa Stark is speaking… only that whichever one opens her mouth, it is me.”

She turned to Jon, eyes shining with triumph and something dangerously close to adoration.

“Let them try to plot against a woman who is always in two places at once,” she said, “and never the one they expect.”