In Greek mythology, Atropos was the oldest of the Three Fates (or Moirae), and was known as the "inflexible" or "inevitable." It was Atropos who chose the mechanism of death and ended the life of each mortal by cutting their thread with her "abhorred shears." She worked along with her two sisters, Clotho, who spun the thread, and Lachesis, who measured the length.
(Forgive the less-than-stellar photo quality. I just wanted to get a quick shot before the con, should the piece sell this weekend.)