LOKI! HOW DARE THEE?! THOU WILL PAY FOR WHAT HATH BEFALLEN THE GOLDEN LAND!!
-- Thor Odinson
Asgard was once home to the mighty race of gods known as the Asgardians. It was ruled by Odin before it's destruction. His two heirs, his son Thor and adopted son Loki, were next in line to rule. Loki, being the son of a Frost Giant, sought to get revenge on Odin for killing his father. On Thor's 20th birthday, the day he was to receive Mjolnir, Loki convinced Surtur to bring upon the Asgardian Ragnarok in order to destroy the golden land. Thor and Loki fought, and were both narrowly saved by an inter-dimensional portal created by the Odin-Force, and were both pulled into Earth-903 just as their home reality was completely destroyed.