Nidhogg

From OMGWiki

Nidhogg is the demons' equivalent of Yggdrasil. In short, Nidhogg is the supercomputer that runs Hell, and is the life-support system for demons who are on Earth. It's assumed that goddesses and gods are not allowed to hack into Nidhogg, much like how demons aren't allowed to hack into Yggdrasil. We get to see the repercussions of doing so in the punishment of Velsper.

In Vol. 22, during the "Honey, I Shrunk the Peorth!" incident, Hild arrives on the scene and is quite amused with the goddesses' attempts to restore Peorth. She reassures the goddesses that their efforts are futile, because Nidhogg was locked with Hild's personal password. So, the only one able to break the curse, was Hild herself.

As of now, not much is known about Nidhogg other than these things.

In Norse mythology, at the roots of Yggdrasil (The World Tree) lived Niddhog (A dragon) which fed on the corpses of the dead and chewed on the roots of Yggdrasil.