Tyrfingr

Tyrfingr (The name is of uncertain origin, possibly connected to the Terwingi) is a magical sword in Norse mythology, which features in the Tyrfingr cycle, which includes a poem from the Poetic Edda called Hervararkviða, and the Hervarar saga ok Heiðreks. The name is also used in the saga to denote the Goths. The form Tervingi was actually recorded by Roman sources in the 4th century.

Story
Svafrlami was the king of Garðaríki, and Óðinn's grandson. He managed to trap the dvergar Dvalinn and Durinn when they had left the rock where they dwelt. Then he forced them to forge a sword with a golden hilt that would never miss a stroke, would never rust and would cut through stone and iron as easily as through clothes.

The dvergar made the sword, and it shone and gleamed like fire. However, in revenge they cursed it so that it would kill a man every time it was drawn and that it would be the cause of three great evils. They finally cursed it so that it would also kill Svafrlami himself.

When Svafrlami heard the curses he tried to slay Dvalinn, but the dvergr disappeared into the rock and the sword was driven deep into it, though missing its intended victim.

Svafrlami was killed by the berserker Arngrímr, who took the sword in his turn. After Arngrímr, it was worn by Angantýr and his eleven brothers. They were all slain at Samsø, by the Swedish champion Hjálmarr, and his Norwegian sworn brother Ǫrvar-Ǫddr; but Hjálmarr, being wounded by Tyrfingr (its first evil deed), has only time to sing his death-song before he dies, and asks Ǫrvar-Ǫddr to bring his body to his beloved Ingibjǫrg, daughter of Yngvi at Uppsalir.

Angantýr's daughter, Hervǫr Angantýsdóttir (by his wife Tófa) was brought up as a bond-servant and remained ignorant of her parentage. Upon learning it, she armed herself as a shield-maiden, and travelled to Munarvoe in Samsø in an attempt to recover her father's weapon. She found it and married King Guðmundr's son, Hǫfundr. Together they had two sons, Heiðrekr and Angantýr. Hervǫr gave Heiðrekr the sword Tyrfingr in secret. While Angantýr and Heiðrekr walked, Heiðrekr showed Angantýr the sword. Since he had unsheathed it, the curse the dwarves had put on the sword made Heiðrekr kill his brother Angantýr. This was the second of Tyrfingr's three evil deeds.

Heiðrekr became king of the Goths. During a voyage, Heiðrekr camped at the Carpathians (Harvaða fjöllum, cf. Grimm's law). He was accompanied by eight mounted thralls, who eventually entered his tent and slew him in his sleep, the third and final of Tyrfingr's evil deeds. Heiðrekr's son, also named Angantýr, caught and killed the thralls and reclaimed the magic sword, finally satisfying the dwarves' curse.

Angantýr was the next king of the Goths, but his illegitimate half-Hun brother Hlǫðr wanted half of the kingdom. Angantýr refused, and Gizurr called Hlǫðr a bastard and his mother a slave-girl. Hlǫðr and 343,200 mounted Huns invaded the Goths (See The Battle of the Goths and Huns). The Huns greatly outnumbered the Goths. The Goths won because Angantýr used Tyrfingr to kill his brother Hlǫðr on the battleground. The bodies of the numerous warriors choked the rivers, causing a flood which filled the valleys with dead men and horses.

Trivia
The curse on Tyrfingr is comparable to that placed on the ring Andvaranaut in the Vǫlsungr cycle.