Asgard is the world of the Aesir, home to the Asgardians, and ruled by Odin. It's more of a "dimensional plane", which exists in parallel with nine other worlds, such as Midgard (the world of humans).
It has been prophesied that Loki will lead Asgard's enemies into the "Eternal Realm" and aid them in destroying it in a final conflict known as Ragnarok, or sometimes referred to as "The Twilight of the Gods".
Loki was determined to fulfill his destiny, but he soon learned from the prophetess Volla who foretold that Ragnarok did come, but only to be opposed by Superman, the "Herald of Nirnaetrelding, the New Dawn". This revelation did little to angered the God of Mischief, who sworn to bring Ragnarok no matter what stood in his way.