[quote=@Raijinslayer]
But Nidhogg isn't strictly a deity, and is noted for being one if the few to not die during Ragnarok. I take to likening Nidhogg as a representation of Entropy, a fundamental force of chaos and destruction that can't be fully stopped or killed, only slowed. I mean, he's known as the Gnawer of Yggdrasil, which is basically the symbol for the order of the universe, so I think my interpretation is valid for the most part.
[/quote]

It is. But again, he's just a soul in a vessel for now. Without a vessel, he has no power. So, after the vessel is gone, sealing him up somewhere, like say, Tartarus, is not that far fetched of an idea.

Just gotta give him something to gnaw on. Like a tree root.