Kunti
Kunti was one of the two wives of Pandu, the other one being Madri. She is the mother of the three Pandavas - Yudhishthira from lord Dharma, Bhima from Vayu and Arjuna from Indra. She was the daughter of king Shurasena, and sister of Vasudeva - the father of Krishna (thus Krishna's paternal aunt). She was given for adoption to king Kuntibhoja.
From Rishi Durvasa, Kunti obtained a mantra, before her marriage to Pandu, through which she could obtain a son from any of the Gods that invites. As soon as she obtained the Mantra, she wanted to test the Mantra even when she was still unmarried. She invoked Surya then, from whom she obtained a son who later came to be known as Karna.