
She was searching for the truth behind the story of the Berserker, wanting to become stronger and tired of feeding and scratching Nidhogg threatened to stab him in the eye. Who was surprised to find him alive for last she heard he had died at the roots of Yggdrasill, to which he did not care for her questions and only wanted to know what she brought him to eat. Having returned to live after his death during Ragnarok, he was visited at his home in Nastrond of Niffleheim by Lady Sif. As Hulk destroyed the machine and killed Nidhogg, it did nothing to retaliate as it was tired of being used as a weapon and wanted to finally die. The only way to defeat them was to destroy the machine and kill Nidhogg. When the Avengers arrived at Skrekklandet, they battled multiple cloned offspring of Nidhogg, but more kept spawning. In the modern day, Nazis had weaponized the body of Nidhogg and used it to create clones of itself. The explosion of Thor's strike was witnessed by Captain America, who was on his way there to destroy a Nazi base. Thor arrived soon afterwards and summoned a giant lightning bolt, which killed and buried Nidhogg. When Nidhogg was gnawing on the roots of Yggdrasill, one of the roots snapped and it created a wormhole that pulled Nidhogg into a small town in Midgard called Skrekklandet. During Balder Odinson's journey to Hel, he encountered Nidhogg and was adversely affected to see what had become of the souls of all those he had vanquished in battle.

Known as the "Eater of the Dead", Nidhogg consumed the souls of those who had fallen in battle. Nidhogg was a giant dragon that lived in Niffleheim, one of the Nine Worlds of Asgard.
