What things causes stupidity,ignorance?

[Angrboda]

One more snake tale: the story of Pārśvanātha, a Jain Tīrthańkara (literally “ford maker” — one who creates a ford across the river of samsara to moksha).

One of the most striking features of these tales of the earlier lives of Pārśvanātha is the emphasis throughout on the ruthless opposition of a dark brother whose development is the very antithesis of that of the savior. Pārśvanātha increases in virtue, but his dark brother, simultaneously, in evil, until the principle of light represented in the Tīrthańkara finally wins, and the brother himself is saved. The enmity between the two is represented as having begun in their ninth incarnation before the last. They had been born, that time, as the sons of Visvabhuti, the prime minister of a certain prehistoric king named Aravinda. And it so happened that their father, one day thinking: “Transitory surely is this world,” went away on the path of emancipation leaving his wife behind with the two sons and a great store of wealth. The elder son, Kamaţha, was passionate and crafty, whereas the younger, Marubhūti, was eminently virtuous (the latter, of course, being the one who is to be Pārśvanātha in the final birth), and so when their king one time had to leave his kingdom on a campaign against a distant enemy, he committed the safety of the palace not to the elder brother but to the younger Marubhūti; and the elder, in sinful anger, then seduced his brother's wife. The adultery being discovered, the king when he returned asked Marubhūti what the punishment should be. The future Tīrthańkara advised forgiveness. But the king, commanding that the adulterer's face should be painted black, had him seated, facing backwards, on an ass, conducted through the capital, and expelled from the realm.

Deprived thus of honor, home, property, and family, Kamaţha devoted himself in the wilderness to the most extreme austerities, not in a humble spirit of renunciation or contrition, but with the intent to acquire superhuman, demonic powers with which to win revenge. When Marubhūti was apprised of these penances, he thought that his brother had at last become purified, and therefore, in spite of the warnings of the king, paid him a visit, thinking to invite him home. He discovered Kamaţha standing — as had been his custom day and night — holding on his upstretched hands a great slab of stone, overcoming by that painful exercise the normal states of human weakness. But when the future Tīrthańkara bowed in obeisance at his feet, the terrible hermit, beholding this gesture of conciliation, was so filled with rage that he flung down the great stone on Marubhūti's head, killing him as he bowed. The ascetics of the penance-grove, from whom the monster had learned his techniques of self-affliction, expelled him immediately from their company, and he sought refuge among a wild tribe of Bhils. He became a highwayman and murderer, and in due course died, following a life of crime.

This grotesque story sets the stage for a long and complicated series of encounters, full of surprises — a typically Indian affair of deaths and reappearances, illustrating the moral theory of rebirth. The wicked Kamaţha passes through a number of forms paralleling those of his virtuous, gradually maturing brother, reappearing time and again to repeat his sin of aggression, while Marubhūti, the future Tīrthańkara, becoming more and more harmonious within, gains the power to accept his recurrent death with equanimity. Thus the dark brother of this Jaina legend actually serves the light …

…According to our serial of tales, then, though both Kamaţha and Marubhūti have died, this death is not to be the end of their adventure. The good king Aravinda, whom Marubhūti had served as minister, was moved, following the death of his officer, to abandon the world and take up the life of a hermit; the cause of his decision being a comparatively insignificant incident. Always pious, he was planning to build a Jaina sanctuary, when one day he beheld floating in the sky a cloud that looked like a majestic, slowly moving temple. Watching this with rapt attention, he became inspired with the idea of constructing his place of worship in just that form. So he sent in haste for brushes and paints with which to set it down; but when he turned again, the form had already changed. A weird thought then occurred to him. “Is the world,” he mused, “but a series of such passing states? Why then should I call anything my own? What is the good of continuing in this career of king?” He summoned his son, installed him on the throne, and departed from the kingdom, became an aimless mendicant; and wandered from one wilderness to the next.

And so he chanced, one day, upon a great assemblage of saints in the depths of a certain forest, engaged in various forms of meditation. He joined their company, and had not been long among them when a mighty elephant, running mad, entered the grove — a dangerous event that sent most of the hermits to the four directions. Aravinda, however, remained standing rigidly, in a profound state of contemplation. The elephant, rushing about, presently came directly before the meditating king, but instead of trampling him, became suddenly calm when it perceived his absolute immobility. Lowering its trunk it went down on its great front knees in obeisance. “Why are you continuing in acts of injury?” the voice of Aravinda then was heard to ask. “There is no greater sin than that of injuring other beings. Your incarnation in this form is the result of demerits acquired at the moment of your violent death. Give up these sinful acts; begin to practice vows; a happy state will then stand in store for you.”

The clarified vision of the contemplative had perceived that the elephant was his former minister, Marubhūti. Owing to the violence of the death and the distressing thoughts that had been harbored in the instant of pain, the formerly pious man was now in this inferior and rabid incarnation. His name was Vajraghoşa, “Thundering Voice of the Lightning,” and his mate was the former wife of his adulterous brother. Hearing the voice of the king whom he had served, he recalled his recent human life, took the vows of a hermit, received religious instruction at the feet of Aravinda, and determined to commit no further acts of nuisance. Thenceforward the mighty beast ate but a modicum of grass — only enough to keep its body and soul together; and this saintly diet, together with a program of austerities, brought it down so much in weight that it became very quiet and emaciated. Nevertheless, it never relaxed, even for a moment, from its devout contemplation of the Tīrthańkaras, those “Exalted Ones” (parameşţhins) now serene at the zenith of the universe.

Vajraghoşa, from time to time, would go to the bank of a nearby river to quench his thirst, and on one of these occasions was killed by an immense serpent. This was his former brother, the perennial antagonist of his career, who, having expired in deep iniquity, had been reincarnated in this malignant form. The very sight of the saintly pachyderm proceeding piously to the river stirred the old spirit of revenge, and the serpent struck. Its deadly poison ran like fire through the loose and heavy skin. But in spite of terrific pain, Vajraghoşa did not forget his hermit vows. He died the death called “the peaceful death of absolute renunciation,” and was born immediately in the twelfth heaven as the god Śaśi-prabhā, “Splendor of the Moon.”

— Heinrich Zimmer, Philosophies of India

(Vajraghoşa is one of my alternate internet names.)