In Greek mythology, the Moirai or Fates are three sisters responsible for determining human destiny. They spin, measure, and cut the thread of life, representing the inevitability of fate. Clotho spins the thread, Lachesis measures its length, and Atropos cuts it, signifying the end of life. The Moirai's role emphasizes that despite human endeavors, one's destiny is predetermined and inescapable, instilling a sense of both fear and acceptance of the life journey's uncertainty.