One fo the most remarkable features of Helheim is the massive and complex subterranean infrastructure below the city, down there molten magma falls and subterranean thunderstorms brew. The architect of these caverns is no other than Kaiju-131, codenamed Nнрhцggr. Sharing genes with fellow serpents Jцrmungandr and Vasuki, Nнрhцggr spends most of his times burrowing through bedrock underneath Seattle, often being responsible for small tremors throughout the region. Nнрhцggrs behavior is noticeable from other inhabitants of Helheim due to the kaiju less aggressive nature, often puzzled by things he has first encounter such as N.M.W drones. The kaijus aloof nature may be the reason why the kaiju isnt scared off by Hels presence like others. Despite that, Nнрhцggr is still treated as a dangerous creature as the venom within his fangs or stinger-like tail rival Thanatos in potency.

https://www.deviantart.com/tyrant28/art/Nidhoggr-Basic-Ref-Sheet-871142801