Dungeon of Yggdrasil Picture

Níðhöggr or "Nidhogg Nagar" is a being which gnaws one of the three roots of Yggdrasill. It is sometimes believed that the roots are trapping the beast from the world. This root is placed over Niflheimr and Níðhöggr gnaws it from beneath.

My Niddhögg does feed from the roots and the wood of the
worldtree but he is not trapped there.
He's more like a guide for those who want to get through
the labyrinth amongst the roots of Yggdrasil.

Should I mention?
Niddhögg is huge, Yggdrasils roots are ENORMOUS.
Just to give you some sense of dimension.
Dungeon of Yggdrasil
Griffin 3
Modern Day Cupid