They ride without looking back, down from the standing stone and through the silent towns over the plains. They ride without looking back, because the yawning rustle and hiss that seethes behind in the curling fog is more than a little unnerving. And Aragorn has a ghost following him. They're all following him, which was, after all, the point, but...there's a ghost, one. Following him.
They take the briefest of pauses to rest themselves, horses and men. Aragorn’s back is strung so tight with tension it takes two tries to swing his leg over the horse, and even Legolas’ customary ease is marked by stiffness. Gimli simply doesn't bother dismounting, just clings to the saddle and mutters something about tough dwarvish constitutions. The army of oathbreakers are restless black char sketches on the ever-shifting fog, roughly echoing the forms they held in life. Aragorn hasn't decided if it's worse when they are faceless, or when their features are all-too discernable. He turns away, but not quickly enough, and a cold breath follows him back up into the saddle.
They ride again, faster than is wise on old, dark roads. Damp cold flows around him, and he thinks his ghost must be riding pillion behind him.
I said that Gondor would see it done, did I not? And the Quest is not yet ended.
Tendrils of fog wisp over Aragorn’s arms, curl over his vambraces. He relaxes his seat a little, and leans into the feel of firm steel at his back.
They ride four days and five nights to the Anduin, to catch the Corsair fleet at Pelargir. Three of those days might as well be nights for all the sun’s power against the Shadow from the east. Their army (Your army, Aragorn. We follow you.) seems to thicken, grows restless under its weight. Muffled cries and hoarse whispers can be heard from the grey host behind them, and still they ride on, haste and dread chasing their heels.
The Corsairs die screaming, or else fling themselves into the river in their terror, and so the dead take them. Aragorn bears the terror of his spectral army because it gives him comfort, too; so great has the power of the Shadow grown that the dead are hope to the living. It is with a heavy heart he relases them from their oaths. The pale king casts down his spear, and he and his shadow host vanish like the memory of a dream.
Yet that evening in his cabin aboard the first ship, Aragorn hears a familiar rough soldier’s voice singing, in tones too cold for the living. Forth rode the king, fear behind him, fate before him. Dim lantern-flame and smoke sketch rather than illuminate the tall form sitting idly at the small table, with a glint of gold at the waist. Beyond the gate the seaward road runs south, and I will come with the wailing gulls from the grey sea’s mouth.
Aragorn sits back in the narrow bed, watching and listening as the lantern wick burns down. Even as it gutters out and he gives in to exhuastion, he can still hear the ghost humming in the dark.
Aragorn’s ranks of oathbound dead may be reduced to one, but he leaps over the side of the black-sailed ship knowing that more than bow and axe protect him.
He cleaves a bloody path northward, Elendil’s banner shining in the fresh sunlight, and the horns of the City guard alter their call from panic to triumph. “The King, the King! The lords of Gondor have returned!”
Dunedain and elves and men of the South behind him, Aragorn reaches Eomer’s side in the midst of the battle, and they breathe for a pace, grin at each other as they lean on their swords. Though he appears unscathed in body, some wild grief shadows the horse-lord’s eyes, even as he clasps Aragorn’s arm. Behind them, the City is battered and scorched, but the tall White Tower gleams over the smoke.
The world of men does not yet fall. A swirl of dust and smoke gusts beside Aragorn and he feels gloved fingers grip his shoulder. ...over death, over dread, over doom lifted. If Eomer is surprised by Aragorn’s spectral shield-mate, he doesn’t show it, but raises his blade in salute to the once-captain of Gondor.
My brother, my captain, the ghost whispers, then laughs out into the bright, bloody day. My king. Boromir faces him, pride and fierce determination in his expression, and Aragorn knows Denethor is dead and there can be no turning back. A moment of doubt assails him, dread for the chinks of his life falling into place and the enormity of the task remaining, but the riddle of Boromir’s dream has led Aragorn to this place; the dead man is still at his side, fulfilling his oaths to both City and Ringbearer, and Aragorn has his own oaths to uphold.
The horns of the City ring out again, a clarion call of triumph and challenge. A new line of the enemy pushes forward, and Eomer’s fey rage flares forth anew, spreading to the other men and sharpening the clamour and blood-haze of the battlefield. Aragorn has no surety that the blows he strikes here will aid those beyond his keeping, but beside him, Boromir glows like a pale-fire brand, grim and bold, and they take up their swords together once more.
If Boromir is spouting poetry, he’s stealing lines from 1) Lament for Theoden, RotK, Ch. 3 “The Muster of Rohan” 2) Legolas’ part of the Lament for Boromir, TTT ch. 1 “The Departure of Boromir” and 3) Burial Song for Theoden, RotK ch. 6/16 “Many Partings”