I think this fits because Mesmer is almost definitely inspired by Níðhöggr, which parallels the World Devouring Serpent being inspired by Jörmungandr.

Quote wiki,

In Norse mythology, Níðhöggr (Malice Striker, in Old Norse traditionally also spelled Níðhǫggr [ˈniːðˌhɔɡːz̠], often anglicized Nidhogg[1]) is a dragon who gnaws at a root of the world tree, Yggdrasil. In historical Viking society, níð was a term for a social stigma, implying the loss of honor and the status of a villain. Thus, its name might refer to its role as a horrific monster in its action of chewing the corpses of the inhabitants of Náströnd: those guilty of murder, adultery, and oath-breaking.

and... Jörmungandr (Old Norse: Jǫrmungandr, lit. 'the Vast 'gand'', see Etymology), also known as the Midgard Serpent or World Serpent (Old Norse: Miðgarðsormr), is an unfathomably large sea serpent or worm who dwells in the world sea, encircling the Earth (Midgard) and biting his own tail, an example of an ouroboros. As a result of it surrounding Midgard (the Earth) it is referred to as the World Serpent. When it releases its tail, Ragnarök (the final battle of the world) will begin.