alot of korean and japanese games have norse mythology up the wazu, take final fantasy and most other RPg's for that matter. Ragnorok itself, as stated earlier, is the norse apocalypse. in FF7, the name of clouds town was clever, Niebelheim, literally means home of cloud, while regarding the realm of nieflheim.
(beware, i'm not a FF fanatic, just happen to know this stuff. i say this, cause most of my references come from FF or other square and enix games.) I believe a few in game items here in Ragnorok are akin to thor's and Odins's weaponry/steeds.
names like Loki, Odin, Thor, and many others are from the norse mythos.
i'm unsure as to what the earth in ragnarok is called, but might it be Midgard? if so, thats basically the realm of humans in the norse mythos.