When Baldur became a man, he started dreaming of his own death. The Norse seeresses once prophesied that the death of God Baldur was the first sign of Ragnarok which meant Norse Pantheon was drawing to an end. Odin and his fellows did attempt to either prevent or prepare for this final battle. They did try to find the way to save Baldur but failed. Asgard's shining god no more shone. No matter what they did, Ragnarok was about to happen.
After the death of Baldur, there should come a great winter that was named "Fimbulwinter". Never before had anyone seen such type of winter. Three winters came in a row without a summer in between. The biting winds would blow the Nine Worlds with snow and rain. Midgard had never been in such condition. The warmth from the sun finally disappeared leaving everything for this bitter cold. Mankind would become desperate for food and other necessities of life. All morals of life vanished into thin air. Everything was pulled back to the age of swords and axes. Bloodshed was everywhere. Brothers killed one another. Everything was for survival.
Wolves Hati and Skoll were allegedly the offspring of Fenrir the Monstrous Wolf. From the beginning of the world, these two wolves attempted many times to chase down the Sun and the Moon, yet failed all the time. It was not until the beginning of Ragnarok that the pair finally caught the Sun and the Moon. They swallowed these two brilliant stars sending the world into blackness.
The dragon-like serpent Nidhogg living under the roots of Yggdrasil started to gnaw at the roots of this Great Ash Tree. Yggdrasil trembled and Jormungand the Midgard serpent started to move his giant move getting ready to emerge from the ocean.
Three roosters will crow: the crimson rooster Fjalar will crow to the Giants; the golden cock Gullinkambi will crow to the gods; and a third cock will raise the dead.
On Ragnarök Odin is killed by Fenrir(a giant monstrous wolf) who is then killed by Odin's son Vidarr.
Thor kills Jörmungandr(The World Serpent) but succumbs to the serpent's poison after taking only nine steps after the battle and falls dead.
Freya is killed by Surtr(the fire giant) The Ruler of Muspelheim(realm of fire) and the fire giants. Soon after, Surtr sets fire to the world with his sword and the Nine Realms fall in flames, ending the cycle of life that began with the gods' act of creation.