Lugh's parents were Cian, son of Dian Cecht, the Danann physician, and Ethniu, daughter of Balor, the evil Fomorian leader. Balor had heard a prophecy that his own grandson would kill him, so he shut Ethniu up in a tower on Tory Island. However, Balor had stolen Cian's magic cow, and wanting revenge, Cian, with the help of the Druidess Birog, infiltrated Ethniu's tower and spent the night with her. Ethniu subsequently gave birth to Lugh.
When Balor heard that his daughter had given birth to a son, he ordered that Lugh be thrown into the sea, but before this could happen, Cian brought his son to either Goibniu, the Danann smith, or Tailtiu, the former queen of the Fir Bolg. Regardless of who he was raised by, Lugh grew up safe from his evil grandfather. One day, Goibniu or Tailtiu told Lugh that Bres, the former Danann king, had lost his throne because Nuada, the previous king, had had his severed hand replaced, and therefore gotten his throne back. Unfortunatly, Bres had gone to Balor to get revenge on the Danann. Lugh decided to warn Nuada of this plot.
Lugh joins the Danann
When Lugh arrived at Nuada's palace, he told the sentry that he wanted to become Nuada's carpenter. The sentry replied that the Danann already had a carpenter. Lugh in turn told the sentry that he was also a historian. The sentry replied that the Danann had that too. Lugh went on to state that he was also a harper, sorcerer, hero, smith, athlete, and so forth. The sentry told Lugh that the Danann had all these things, but when Lugh asked if they had anyone who was a master of all these skills, the sentry said no and let Lugh into the palace. Nuada, seeing that Lugh had potential, let him join the Danann.