The defensive fortress which the gods build about the middle portion of the earth allotted to men in order to protect mankind from the giants. Midgard ("middle world") is on the same level as Nidavellir (land of the dwarfs), Svartalfheim (land of the dark elves/dwarfs) and Jotunheim (the land of the giants).
When I was looking into the Vikings I came across a myth, this helped me gathered the idea for the Vikings back story. I don't have a name for my Viking character, so for the time being he will just be called hero, the same applies to my villain so he will be called the bad guy and the same for the Sidekick who will be classed as sidekick.
The story is that Hero’s duty is to guard Midgard from evil, but he gets overpowered by the bad guy who releases the giants all over the world. As punishment by the gods for heroes mistake he must go out form Midgard and travel the world getting back the giants that have escaped. He will be accompanied with a dark Elf who swore to give his life to the gods for sparing him many years ago.