It ends like this
Robin smiled at Usopp as he passed by her deckchair. He gave her a sad, pained smile in return, but didn't pause to chat as he would have before, even though she was obviously idling, the book in her lap closed. Instead, the smile on his lips died, chased away by a pained expression. He continued on his way, his shoulders slumped, barely acknowledging it when he bumped into Franky on his way across the deck.
Robin let the smile on her lips slip away, gently stroking the spine of her book.
Nine days, and the silence still covered the ship like a blanket of grieve. She had expected that, even though she suspected all – with the possible exception of Luffy – had had to suffer through the death of a loved one, but the unexpected loss of their nakama had shaken them all, and especially her younger crew mates had trouble coping.
Or maybe it was less the unexpected, and more the never thought of as possible death of their nakama that left her friends reeling.
But Robin had spend years on the Grand Line, and she new of the unpredictably of the Devil Fruits. She didn't need scientific texts telling her of unanticipated drawbacks, of weaknesses that condemned the wielders of even the most obscure and powerful abilities to death. No, she thought, gazing at the book in her lap in contemplation, she had witnessed the tragedies caused by the Devil Fruits first-hand.
None, not even those that seemed to promise eternal life protected from death forever, and all it took was to find that one, fatal drawback to destroy a life.
And in this case, Robin thought, leaning back in her chair and letting the sun fight the all too familiar chill of grieve, a fatal injury inflicted underneath the crushing weight of the sea; an injury that would have been inconsequential on land, was this one drawback, that fatal weakness. A broken neck, crushed bones; injuries usually easily fixed had taken the life of their nakama.
Bones, Robin thought, gazing at the blue sky and listening to the soft rush of the waves, clearly audible over the silence on deck, broke all too easily.