Prior to the story Rusty was at some point a soldier, though he seems to have become tired of the military.
Rusty is introduced in Ugly Monsters where he is on watch. Returning inside the mall he flees upon Bug's attack. Managing to escape the mall he proceeds to accidentally shoot Annika (when he was actually aiming for Jan). He then finds himself surrounded by zombies, though is rescued by Greybane.
Eventually they make it back to the colony.
Settling into a new apartment, Rusty adjusts to life in the colony well, though he is moved to new lodgings relatively quickly.
Rusty heads into the colony, where he subsequently wastes all of his credits.
Rusty makes his next appearance in Target Practice where he is shown to be very capable with a gun. When asked about joining the New Hammerston army he curtly refuses.
Rusty starts the scene in Mack's, where he is looking to get a tab. He later joins Jake, Nathan, Annika and Scott for breakfast.
Later he is present when Aaron asks Annika out to lunch. When alone he meets Joe and Bernie, who are looking for Annika.
Rusty is generally shown to be quite a selfish, cruel figure. He is willing to sacrifice others for his own well being and can be overly harsh at times.
Despite this he does seem to have a softer side. After all their troubles he seems to have grown attached to Annika and Nathan, looking after them upon their arrival in New Hammerston (though he still wastes all their credits).
Rusty generally doesn't get on with most people. He often clashes with those with a more optimistic outlook than him, such as Aaron.
Although they have a mixed background, Annika seems to feel safe with Rusty around.
While he has been quite harsh to Nathan at points, the young boy seems to have some respect for him.
Rusty has no superhuman abilities, though he is competent with the crossbow (using it on several occasions to good effect).
Having once been in an army of sorts he is very capable with using weaponry as well.