Nix

Nyx is the name of Roxy Lalonde's browser of choice (although it is misspelled as "Nix" on her computer), and so it is to be presumed that it is also the name of the Denizen of her land. If this is the case, then Nyx would likely be the Denizen associated with Void, and thus presumably also Equius Zahhak's denizen in the Land of Caves and Silence.

In Greek mythology, Nyx is the primoridal goddess of the night.