Magic sword
In mythology, legend or fiction, a magic sword is a sword with magical powers or other supernatural qualities. Renowned swords appear in the folklore of every nation that used swords.
In some traditions, the sword is ascribed no powers of its own. It is famous because it is the hero's sword, or because of its origin, as when a god gives it to the hero. Other swords keep their wielders safe or destroy their enemies. A more localized motif is the sword that has been broken and must be reforged, commonly found in Northern Europe. Such a sword symbolizes the initial defeat and loss of honor of its wielder. Subsequent victory and the restoration of honor is achieved by reforging it, either at the wielder's hand or that of his heir.
History
It is probable that the roots of the sentient weapon myths stem from ancient peoples' belief that sword making and metallurgy was in fact a magical process. Through the fires of the forge a lump of earth was transformed into a shiny usable object that could be hammered into many shapes. Extending further from the transformation of ore into metal, the difficulty of actually obtaining a quality blade; which took intense concentration and skill added to its esoteric qualities. While any blacksmith could manufacture a knife or an axehead only a swordsmith could create a high quality sword. The secrets of doing so were jealously guarded as well as formulas for alloys.The skill necessary to forge a balanced blade - one which is not too brittle or too soft and able to hold a usefully sharp edge - in the age before automated machines, blast furnaces, and the knowledge of molecular chemistry made the creation of a sword seem almost miraculous. A few degrees too hot or too cold within a very limited temperature range, which could only be discerned by the glowing hue of a hot billet, could make or break a sword. A lack of expertise in knowing when and how to apply carbon and flux and quench the blade could ruin weeks of work. Thus the swordsmith almost felt like he was one with his work, giving the process his complete devotion of concentration and thought. This led to the belief that he was actually imbuing the blade with an essence of his spirit. In Japan, the swordsmiths were so concerned with this belief that they would undergo purification rituals and meditation before even attempting to start a new blade, for fear that they might inadvertently create an evil sword.
The Vikings prized their swords above all other things, handing them down from generation to generation and giving them names. The value of the blade was not only determined by its quality but also by how many battles that it was used in. Polynesian people such as the Māori also had comparable reverence for their weapons. They believed a weapon contained a spiritual force called mana and that the weapon held the spirits of its maker, its line of owners and also stole the spirits of those it killed. These weapons where highly prized for their mana and cherished as heirlooms. The Samurai of Japan believed that their swords had their own soul that could possess them. It was not the wielder but their swords that desired to kill; Samurai were just the instrument that the sword used to complete that task. Since most of them were Buddhists, that train of thought gave them some peace of mind in their killing vocation.
Later, as the concept of demons, spiritual possession, and elementals entered the realm of mythological themes, it was only a natural leap to attribute magical properties of the swords of folklore to indwelling spirits.
Magic swords may exhibit various degrees of sentience, from being merely influenced by the wielder to being able to think for itself or even control its owner.
Biblical
The Bible relates in the Book of Genesis how God, seeking to deter Adam and Eve from returning to the Garden of Eden, "placed at the east of the garden of Eden Cherubim and a flaming sword which turned every way". By some accounts, the Cherubim are replaced with the Archangel Michael, who wields a similar weapon.King David was given the sword of the slain giant Goliath by the priest Ahimelech, to which was attached extra-biblical mythology and traditions.
In the Book of Revelation, Jesus is symbolically described wielding a double-edged sword that proceeds out from his mouth, in reference to the "sword of the spirit" which is the "word of truth".
Mythological
Arthurian
In the legend of King Arthur, the king himself is related to two magical swords, in most variants. The first is the Sword In the Stone. Only Arthur could draw it out, thereby proving that he is the rightful king. In some tales, this is his only sword. In most variants, this sword was then broken, and he receives from The Lady of the Lake a new sword called Excalibur, arguably the most famous of magic swords. Caliburn was the original name of Excalibur. In Welsh legend, Arthur's sword is known as Caledfwlch.Geoffrey of Monmouth's History of the Kings of Britain is the first non-Welsh source to speak of the sword. Geoffrey says the sword was forged in Avalon and Latinises the name "Caledfwlch" as Caliburnus. When his influential pseudo-history made it to Continental Europe, writers altered the name further until it finally took on the popular form Excalibur. However, in other variants Excalibur itself is the sword in the stone. It is not clear from the various accounts of the Arthur legend whether Excalibur itself was possessed of magical powers or merely had a magical origin, though its scabbard protected its bearer from physical harm. Many interpretations of the legend appear to endow Excalibur with a cutting strength and durability beyond that of ordinary weapons.
In Wolfram Von Echenbach's Parzival, the eponymous hero is given a sword by the Grail king, Anfortas. Parzival's cousin explains that "“The sword will withstand the first blow unscathed; at the second it will shatter. If you then take it back to the spring, it will become whole again from the flow of the water. You must have the water at the source…If the pieces are not lost and you fit them together properly, as soon as the spring water wets them, the sword will become whole again, the joinings and edges stronger than before.”
Chinese
Ancient Chinese mythology relates the tale of Lü Dongbin, who "slew dragons" with a magic sword and performed "freak feats" with it.Germanic
In Norse mythology, the god Frey "possessed a magic sword that struck out at Jotuns of its own accord". Many other swords appear in Norse legend in the hands of heroes.Tyrfing appears in the Hervarar Saga. Svafrlami was the King of Gardariki, and a grandson of the god Odin. He caught the dwarves, Dvalin and Durin, and 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 dwarves 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 used and that it would be the cause of three great evils. They also cursed it so that it would kill Svafrlami himself. It would cost the life of not only Svafrlami, but also the life of the Swedish hero Hjalmar.
A similar sword to Tyrfing is Dáinsleif, a sword from the legend of the eternal battle Hjaðningavíg, made by the dwarf Dáin. Like Tyrfing, Dainsleif gave wounds that never healed and could not be unsheathed without killing a man. There is also Mistilteinn, a sword from the Hrómundar saga Gripssonar, which could never go blunt and which Hrómund won from the undead witch-king Þrainn. Like Tyrfing, it was taken from a barrow-wight.
The various iterations of the story of the Völsungs include several magic swords. The first magical sword which enters the story is Gram, stuck by Odin into the tree Barnstokkr in the hall of the Völsungs. Only Sigmund could pull it out. This caused considerable envy and conflict. Eventually, Sigmund fought Odin disguised as an old man, and Odin shattered the sword. Sigmund left it for his son Sigurd, who reforged it to kill Fafnir. In the Nibelungenlied, Sîfrit discarded Gram in exchange for another magic sword, Balmung.
The legendary smith Wayland Smith forged the magic sword Mimung, which appears both in the Anglo-Saxon poem Waldere and in the German/Scandinavian Þiðrekssaga.
Beowulf wielded the sword Hrunting that was according to the poem annealed in venom. The sword was useless against Grendel's Mother. In desperation Beowulf grabbed a giant sword of great age and with it took off the head of the she-monster.