A lil something spooky. Anx is a Fluxborn, a creature born from, as the name says, Flux. Best way to describe Flux in a nutshell is when someone makes a wish and it's not counter-balanaced using Equivalent Exchange, this chaos energy is made an all manner of things can happen. Anxiety is one of them.

I do have a couple pages on Equivalent Exchange, Wishes and Flux, if you wanna read up on that.
https://www.worldanvil.com/w/exstellarverse-28nerd-union29-zeta-neubourn/a/the-three-laws-and-equivalent-exchange-article
https://www.worldanvil.com/w/exstellarverse-28nerd-union29-zeta-neubourn/a/flux-article