For Nix and Vess, every day was a struggle for survival.
Nix was close to Vess; she was his motivation, his best friend, his only family, and as such, he protected her fiercely. Where she went, Nix went. While Nix appeared "cute," he could turn feral and vicious when he needed to be. Often, Nix's mood reflected Vess'.
Nix could activate switches or buttons, distract guards, and even grab weapons to bring back to Vess.
Nix is voiced by Dee Bradley Baker. The script for Nix consisted of lines such as "curious squeak" and "relaxed chirp." Baker was allowed to interpret these lines when providing sound effects.