King Niðhad, Níðuðr or Niðung was a cruel king in Germanic legend. He appears as Níðuðr in the Old Norse Völundarkviða, as Niðung in the Þiðrekssaga, and as Niðhad in the Anglo-Saxon poems Deor and Waldere.
The legend of Níðuðr and Wayland also appears on the Gotlandic Ardre image stone VIII from the 8th century and possibly on the front panel of the 7th century Anglo-Saxon Franks Casket. However, Austin Simmons has recently argued that it is not Niðhad who is depicted, but his daughter Beadohilde (twice).
In Völundarkviða, Níðuðr appears to be a king of Närke (the Njars) and captures Völund. Níðuðr orders Völund hamstrung and imprisoned on the island of Sævarstaðir. There, Völund was forced to forge items for the king. Völund's wife's ring was given to the king's daughter, Bodvild, and Níðuðr wore Völund's sword.
For revenge, Völund killed the king's sons when they visited him in secret, fashioned goblets from their skulls, jewels from their eyes, and a brooch from their teeth. He sent the goblets to the king, the jewels to the queen and the brooch to the kings' daughter. When Bodvild took her ring to him to be mended, he took the ring and seduced her, fathering a son and escaping on wings he made.
In the Þiðrekssaga, Niðung is the king of Jutland. A master smith named Velent arrived in Niðung's kingdom, and Niðung graciously accepted Velent as a servant at his court. One day Velent had lost Niðung's knife, but he secretly made another one for the king. When Niðung discovered that his knife cut better than it used to, he enquired about this with Velent. The smith lied and said that it was Amilias, the court smith, who had made it.