Veeravati
Veeravati was the only sister of seven loving brothers. Newly married, she kept her first Karwa Chauth at her parents' home, fasting without food or water. By evening she was faint with hunger and thirst, and her brothers could not bear to see her suffer. They lit a lamp behind a pipal tree, or held a mirror in a sieve, so that it looked like the rising Moon, and told her it had risen. She offered water to it and ate.
At once news came that her husband had died. Weeping, she set out for his home. On the way the goddess Parvati, or Indrani in some tellings, met her and told her that she had broken her fast before the true moonrise. Veeravati refused to let her husband's body be burned; she sat by it for a year, keeping every Chauth fast, and on the next Karwa Chauth she kept the fast perfectly. By the goddess's grace her husband came back to life.
Karva
A devoted wife named Karva lived by a river. One day, as her husband bathed, a crocodile seized his leg. Karva ran and bound the crocodile with a cotton thread, by the power of her devotion, and went to Yama, demanding that he send the crocodile to hell and spare her husband. When Yama hesitated, she threatened to curse him. Yama, afraid of the power of a faithful wife, did as she asked, and her husband lived long. The festival is named after her, and after the karwa, the pot used in its puja.