Numerous gods are mentioned in the source texts such as the hammer-wielding, humanity-protecting thunder-god Thor, who relentlessly fights his foes; the one-eyed, raven-flanked god Odin, who craftily pursues knowledge throughout the worlds and bestowed among humanity the runic alphabet; the beautiful, seiðr-working, feathered cloak-clad goddess Freya who rides to battle to choose among the slain; the vengeful, skiing goddess Skaði, who prefers the wolf howls of the winter mountains to the seashore; the powerful god Njörð, who may calm both sea and fire and grant wealth and land; the god Frey, whose weather and farming associations bring peace and pleasure to humanity; the goddess Iðunn, who keeps apples that grant eternal youthfulness; the mysterious god Heimdall, who is born of nine mothers, can hear grass grow, has gold teeth, and possesses a resounding horn; the jötunnLoki, who brings tragedy to the gods by engineering the death of the goddess Frigg's beautiful son Baldr; and numerous other deities.
Most of the surviving mythology centres on the plights of the gods and their interaction with various other beings, such as humanity and the jötnar, beings who may be friends, lovers, foes or family members of the gods. The cosmos in Norse mythology consists of Nine Worlds that flank a central cosmological tree, Yggdrasil. Units of time and elements of the cosmology are personified as deities or beings. Various forms of a creation myth are recounted, where the world is created from the flesh of the primordial being Ymir, and the first two humans are Ask and Embla. These worlds are foretold to be reborn after the events of Ragnarök when an immense battle occurs between the gods and their enemies, and the world is enveloped in flames, only to be reborn anew. There the surviving gods will meet, and the land will be fertile and green, and two humans will repopulate the world.
Norse mythology has been the subject of scholarly discourse since the 17th century when key texts were brought to the attention of the intellectual circles of Europe. By way of comparative mythology and historical linguistics, scholars have identified elements of Germanic mythology reaching as far back as Proto-Indo-European mythology. In the modern period, the RomanticistViking revival re-awoke an interest in the subject matter, and references to Norse mythology may now be found throughout modern popular culture. The myths have further been revived in a religious context among adherents of Germanic Neopaganism.