a son of Hyrieus by the nymph Clonia, brother of Lycus and Orion, and husband of Polyxo, by whom he became the father of Antiope. (Apollodorus iii)
According to others Antiope was the daughter of the river-god Asopus. Antiope was carried off by Epopeus, king of Aegialeia; and Nycteus, who, as the guardian of Labdacus, was staying at Thebes, took revenge by invading with a Theban army the territory of Sicyon: but he was defeated and being severely wounded, he was carried back to Thebes where, previous to his death, he appointed his brother Lycus guardian of Labdacus, and at the same time demanded of him as a duty to take vengeance on Epopeus. But the latter died before Lycus could fulfil his promise.
When Labdacus had grown up, Lycus surrendered the government to him; but as Labdacus died soon after, Lycus again became the guardian of his son, Laius, but was expelled by his own great-nephews, Amphion and Zethus.
A very different account is found in Apollodorus iii, for according to it, Nycteus and Lycus were the sons of Chthonius, and were obliged to quit their country on account of the murder of Phlegyas.
They then settled at Hyria; but Lycus was chosen commander by the Thebans, and usurped the government which belonged to Laius, and in which he maintained himself for twenty years, until he was slain by Amphion and Zethus.
Nycteus made away with himself in despair, because his daughter, who was with child by Zeus, fled to Epopeus at Sicyon but before he died, he commissioned Lycus to take vengeance on Epopeus.
Lycus promised, and kept his word, for he slew Epopeus, and
kept Antiope as his prisoner. According to Hyginus (Fab. 157),
Nycteus and Lycus were the sons of Poseidon and Celaeno.