Nemesis is the Goddess of divine revenge. She sought retribution against human pride, arrogance, and evil deeds. In a Greek lyric from 5th B.C., it is said: “I pray that to their share of noble fortunes he [Zeus] send no Nemesis of jealous will, but in prosperity and free from ills, exalt them and their city.” (Pindar, Olympian Ode 8. 86 ff, trans. Conway).
She is sometimes represented as the daughter of Nyx (the night): “Deadly Nyx bore Nemesis (Envy) to afflict mortal men” (Hesiod, Theogony 211 ff, trans. Evelyn-White, Greek epic C8th or C7th B.C.). She is sometimes the daughter of Okeanos (Oceanus), and at other times the daughter of Zeus. In Greek myth, Zeus rapes his daughter Nemesis:
“Nemesis, as she fled from Zeus’ embrace, took the form of a goose; whereupon Zeus as a swan had intercourse with her. From this union she laid an egg, which some herdsman found among the trees and handed over to Lede. She kept it in a box, and when Helene was hatched after the proper length of time, she reared her as her own.” 
“Rich-haired Nemesis gave birth to her [Helene] when she had been joined in love with Zeus the king of the gods by harsh violence. For Nemesis tried to escape him and liked not to lie in love with her father Zeus the son of Kronos; for shame and indignation vexed her heart: therefore she fled him over the land and fruitless dark sea. But Zeus ever pursued and longed in his heart to catch her. Now she took the form of a fish and sped over the waves of the loud-roaring sea, and now over Okeanos’ stream and the furthest bounds of Earth, and now she sped over the furrowed land, always turning into such dread creatures as the dry land nurtures, that she might escape him.” 
Schwartz Salant (1982) speaks of the relationship of Nemesis to envy. Salant states that in the myth of Narcissus, Nemesis represents the curse of Envy. In the tale, Echo prays to Nemesis when she is rejected by Narcissus. Nemesis punishes Narcissus for his ‘unfeeling heart’ . The myth is as follows:
“Narkissos, a son of Cephissus and the nymph Liriope of Thespiae. He was a very handsome youth, but wholly inaccessible to the feeling of love. The nymph Echo, who loved him, but in vain, died away with grief. One of his rejected lovers, however, prayed to Nemesis to punish him for his unfeeling heart. Nemesis accordingly caused Narcissus to see his own face reflected in a well, and to fall in love with his own image. As this shadow was unapproachable Narcissus gradually perished with love, and his corpse was metamorphosed into the flower called after him narcissus. This beautiful story is related at length by Ovid (Met. iii. 341, &c.). According to some traditions, Narcissus sent a sword to one of his lovers, Ameinias, who killed himself with it at the very door of Narcissus’ house, and called upon the gods to avenge his death. Narcissus, tormented by love of himself and by repentance, put an end to his life, and from his blood there sprang up the flower narcissus (Conon, Narrat. 24). Other accounts again state that Narcissus melted away into the well in which he had beheld his own image (Paus. ix. 31. § 6); or that he had a beloved twin sister perfectly like him, who died, whereupon he looked at his own image reflected in a well, to satify his longing after his sister.” Eustathius (ad Hom. p. 266) says that Narcissus was drowned in the well. 
- Pseudo-Apollodorus, Bibliotheca 3. 127, trans. Aldrich, Greek mythographer C2nd A.D., theoi.com, obtained from theoi.com, on January 12th, 2013.
- Stasinus of Cyprus or Hegesias of Aegina, Cypria Fragment 8, Greek epic C7th or C6th B.C., trans. Evelyn-White, theoi.com
- Schwartz–Salant, Nathan (1982), Narcissism and Character Transformation: The Psychology of Narcissistic Character Disorders.
- Dictionary of Greek and Roman Biography and Mythology