Who Lived Inside Yggdrasil Tree of Life?

Yggdrasil Tree of Life held the Nine Worlds within its branches. But are there any creatures that dwelled inside Yggdrasil? The answer was yes. In the Grímnismál poem, Odin spoke of many creatures that made Yggdrasil become their home. From the top to the root of Yggdrasil, there were certain creatures that lived. Because of these creatures, Yggdrasill "suffered more agony than any man knows".

There were four types of creatures that lived inside Yggdrasil: a Hawk, a Squirrel, four Deers, and a Dragon. 

Nidhogg

Nidhogg was one of the most famous dragons in Norse mythology. It was quite unclear whether Nidhogg was a dragon or a serpent. Anyway, Nidhogg was a long and giant creature that gnawed the roots of Yggdrasil. His goal was to make Yggdrasil tremble and fall. Nidhogg joined the Ragnarok in the army of the giant against the gods. Nidhogg lived somewhere near the well of Hvergelmir Well, one of the most important Yggdrasil Wells. 

Vedfolnir

Vedfolnir was a hawk that sat between the eye of an eagle sitting in the branches of Yggdrasil. The hawk was known for sending insults with the dragon Nidhogg, who also lived in Yggdrasil tree. A squirrel would carry the insults from Vedfolnir down to Nidhogg and back. 

Ratatosk

Ratatosk was the squirrel that dwelled inside Yggdrasil. This squirrel was supposed to spread gossip and carry insults between Nidhogg and Vedfolnir. Ratatosk found his pleasure in carrying such type of message. That was why Nidhogg and Vedfolnir just remained foes forever. 

Dain, Dvalin, Duneyr, and Durathror

Dain, Dvalin, Duneyr, and Durathror were the names of four full-grown wild male stags that lived in Yggdrasil. The colour of four stags was reddish. They made Yggdrasil suffer by biting the tree branches and leaves, even the highest ones.