Lachesis

Lachesis was the second of the Fates, the three sisters who ruled the destiny of mortals. Her function was to measure the cords of their lives.

Lachesis measured the cords of all the Doctor's lives, and saw that his lives would end because of the trust others placed in him. Some of the threads were long, others short, and some were mysterious even to Lachesis, as she could not see where they began or ended.

When the universe was ravaged by a war between gods, such as the Olympians and the Osirans, Lachesis and her sisters protected endangered worlds by removing them from the universe and storing them temporarily inside impermeable crystal spheres. (PROSE: The Spindle of Necessity)