Gandhari voluntarily blindfolded herself throughout her married life. Her husband Dhritarashtra was born blind, and on meeting him and realizing this, she decided to deny herself the pleasure of sight that her husband could never relish.
Gandhari bore a hundred sons, (collectively known as the Kauravas), and one daughter Dushala who married Jayadratha. The Kaurava, principally Duryodhana and Dushasana, were the villains of the Mahābhārata, and were all killed in their war against their cousins, the Pandava, at Kurukshetra.
Although Gandhari's sons were portrayed as villains, the Mahābhārata attributes high moral standards to Gandhari. She repeatedly exhorted her sons to follow dharma and make peace with the Pandavas. Gandhari was especially close to Kunti who respected her like an elder sister.
Gandhari made a single exception to her blindfolded state, when she removed her blindfold to see Duryodhana rendering his entire body except his loins invulnerable to any foe. This was however to prove fruitless as Bhima smashed Duryodhana's thighs in their decisive encounter on the eighteenth day of the Kurukshetra battle, a move both literally and figuratively below the belt.
Gandhari was also devout; in particular an ardent worshipper of Lord Shiva. Gandhari's sacrifice of her eyesight and her austere life was to grant her great spiritual power. Gandhari's anguish in the loss of her hundred sons resulted in her cursing Krishna in effect ensuring the destruction of the Yadavas. It is also said that through a small gap in the napkin in which her eyes were blindfolded, her gaze fell on Yudhisthira's toe. The toe was charred black due to her wrath and power. Gandhari ended her life with her husband and her sister-in-law Kunti in the Himalayas, where they died in a forest fire.