Udaeus (Ancient Greek Οὐδαῖος) was one of the five surviving Spartoi — the "sown men" who sprang fully armed from the dragon's teeth Cadmus sowed at Thebes. With Echion, Chthonius, Hyperenor, and Pelorus he helped found the city; later Theban houses, including Teiresias' line in some genealogies, claimed descent from him.
Adapted from Wikipedia, "Dragon's teeth (mythology)" · CC BY-SA 4.0
I.The sown men
After Cadmus killed Ares' dragon at the Theban spring, Athena (in Apollodorus) told him to sow half the teeth. Armed men rose from the furrows; Cadmus cast a stone among them, and they fought until five remained: Echion, Udaeus, Chthonius, Hyperenor, and Pelorus.
Hellanicus instead has only five Spartoi arise, with no mutual slaughter. The survivors help Cadmus found Thebes; Cadmus still serves Ares eight years for the dragon's death before receiving Harmonia.
II.Descendants
Echion marries Agave and fathers Pentheus; other Spartoi seed later Theban aristocracy. One tradition holds that Spartoi descendants bore a dragon-like bodily mark — Creon uses it to recognise Maeon. Udaeus himself is remembered chiefly as one of the five founders rather than as a solo protagonist.
The Jason episode at Colchis reuses Athena's remaining teeth but yields no lasting Spartoi house — that Colchian crop destroys itself. The atlas id udaeus is the Theban sown man, distinct from chthonius-spartos, hyperenor-spartos, pelorus-spartos, and echion.