For Fifi.
A swoosh of a blade, a splash of blood, black, not red, leaving a trail on his sword and in the air as Fíli turns towards another foe. This is the dance the Khazad are masters of, the dance of death, a blade, a shield, a life snuffed out, a life struggling to burn for a little longer.
He turns and sees Thorin, surrounded by enemies, and without thinking he leaps to his uncle, to aid Thorin with his blade, to protect Thorin with his shield. Fíli knows that his uncle would have tried to stop him, but Thorin is busy fighting and he does not quite notice. He understands why Thorin would do that, understands all too well, because every now and then his gaze finds Kíli on the battlefield, to make sure his younger brother is not wounded. Fíli understands, because every time he glances at Kíli he sees that little dwarfling whom he helped learn to walk, to skate, to fight, a small light wooden sword in small chubby hands. And should - Mahal preserve! - should Kíli fall, defending him, Fíli would never forgive himself.
He understands, but still he leaps to Thorin's side, because it is not a matter of understanding nor reason but that of heart and his whole being, because Thorin is his uncle, his mother's brother, his kin, his blood. Because Thorin is like a father to him, and as the heir of Thráin and Thrór and Durin he is like a father to Durin's folk, and it is duty and instinct to protect the father.
Thorin notices and yells at him, and Fíli looks at his uncle apologetically, but does not fall back. He remains by Thorin's side because every time he glances at Thorin he sees that great proud dwarf who leaned over him and helped him learn to fight, a small light wooden sword in Fíli's small chubby hands. He remains by Thorin's side because it is fitting that he should repay the debt by fighting for his uncle now, a heavy iron sword in his big strong hands.
Thorin yells at him and Fíli smiles to let his uncle know it is all right, that maybe this is not how the world is meant to be but for him it is all right. Because they are family, and it is only natural to protect family, and Fíli would rather die himself - without regrets and without fear, with a proud smile on his face - than allow Thorin to die for him.
From the corner of his eyes he notices a movement, much too late, and smiles at Thorin again, to let him know it is all right. There is a sudden cry and a blur and a glint of a blade. There is red blooming on the metal of the armour like a terrible flower as Kíli falls to the ground, looking at Fíli apologetically and smiling at him to let him know it is all right, because every time Kíli glances at him, he sees the proud big brother who leaned over him and helped him learn to fight, a small light wooden sword in Kíli's small chubby hands.
Fíli cries out and blinks away tears as he learns, irreversibly and in the most painful and cruel way, that is not all right.