Item from One Piece by Eiichiro Oda
A piece of paper made from a person's fingernail clippings that always points toward that person, no matter where they are in the world. Burns away and shrinks as the person approaches death. The paper of life.
Vivre Cards are one of the most emotionally resonant inventions in One Piece. The technology is simple — paper infused with a person's life force through their fingernails — but the implications are profound. Ace gave Luffy a Vivre Card when they parted, and watching it burn was how the audience tracked Ace's deteriorating situation before the Paramount War. Lola gave Nami her mother's (Big Mom's) Vivre Card, which became crucial during the Whole Cake Island arc. The card doesn't lie: if someone is dying, you watch the paper burn. If they're alive, it points the way. In a world without reliable communication across vast oceans, Vivre Cards are the closest thing to knowing — really knowing — that someone you love is still alive.
A small, seemingly ordinary piece of paper. When placed on a flat surface, it slides toward the person it's linked to. Tear off a piece and both halves point toward each other. As the linked person weakens or nears death, the paper burns at its edges — shrinking steadily. When they recover, the paper regrows. If the person dies, the paper burns away to nothing. Luffy's Vivre Card burning during Impel Down and Marineford was how the crew knew he was in mortal danger.
Also known as: Vivre Card, Paper of Life, Life Paper