Rust is an urstacean, an amalgam of bear, crab, and human. She is tall and wide, with sparse bristly brown fur growing through a hard exoskeleton, a blocky head, two sets of arms, and a stout beak with bear's teeth behind it.

Rust likes Chrome’s DownBeat music because it makes her exoskeleton rattle.

She still has a great deal of equipment from her mercenary career, including a PPD that she lends to Chrome.

She can drink a lot and always seems to have room at the bar, no matter how crowded it may be.

Urstaceans are parthenogenetic, with colonies made up of clones of the colony queen. Rust is proud of this fact, and cheerily admits that she doesn’t even have genitals.