Walder Frey is pitiful, requiring to be carried to the block where Sansa waits, clad in white, sword in hand. His time in the cells of Riverrun and Winterfell have not improved him in appearance; though he has not decreased in size his skin now hangs off him like a pasty, greasy garment. He has been dressed in all his lordly finery for the occasion, a doublet with the bridge and towers of the Freys blazoned across the massive expanse of his torso, long stringy hair cropped about the ears.
'Lord Frey,' she nods her head, because, criminal, traitor, kingslayer, and whatever else, he is still Lord of the Crossing until she relieves him of that title along with his head.
'My father always said that 'the man who passes the sentence should swing the sword'. And I am no man and this is no longer my forefathers' sword, but in these times of war and rebirth we must make do with what we have.' He begins to shake then, and with a shriek the Late Walder Frey begins to stumble away, barely getting a metre before he is grabbed and unceremoniously brought back to the block.
Lord Clegane (Because he is Lord Sandor Clegane now, for despite the rumours of Robert Strong, the man they call the Mountain that Rides is dead with his head rotting in the sweltering heat of Dorne) holds him down.
Her court is a silent one, so the softest rainfall against the castle's stones sounds like a thunderstorm. Everyone down to the cowherd has stopped work today, crowding around Winterfell to wait for news of the Late Lord Walder Frey's death and it sends a rumble of disquiet through her, reminding her of another execution with the same metal. But they are silent spectators. No ones makes a sound at the pathetic fool brought to his knees just as they remained silent as his kin fell before him.
This is justice, it is not theatre for their entertainment.
'I, Sansa of House Stark, the First of her Name, Queen of the North, the Riverlands, the Vale, the Andals, and the First Men, Lady of Winterfell, do sentence you, Lord Walder of House Frey, to die for the crimes of kingslaying, treason, and murder. Do you have any final words?' The man seems mute, instead he makes several rasping sounds and seems to collapse onto the block.
The sword comes down in a single stroke. It is clean and as close to painless as she thinks it can get. For that she is grateful. The red blood trickling across the ground has already began to climb the white expanse of her skirt, staining it a brilliant crimson. His head will be mounted on a pikes along with those of his family along the Kingsroad as a warning to those who would challenge her reign.
(Sansa is her father's daughter to the bone, but she spent too long in King's Landing to be wary of a little blood.)