The Smoke isn't just made up of a love triangle (Tally-David-Shay) and parents (Maddy and Az)—there are some ordinary people there. Well, as ordinary as rebels and runaways can be. There are a bunch of characters in the Smoke, but only a few get named.
Ryde and Astrixare two of Shay's friends from the city days. They play the role of audience most of the time: when Tally comes to the Smoke, they listen to her amazing (and partly made-up) adventure story of how she got to the Smoke. And Ryde and Astrix are also the audience for Shay's prettiness. When Shay is pretty, these guys are in awe of her: "Ryde and Astrix watched her silently, a bit awestruck by her looks" (47.38). So that's Ryde and Astrix—constantly watching and listening to other people.
Croy is another matter entirely. Aside from having an awesome name, he's from the city. And his main role in this book is to doubt Tally's story. When they're cutting through some wood to harvest the metal (the metal crop is very important to the Smoke), Croy sneakily asks her about some things that don't fit in her story, like how much SpagBol she had left.
In fact, we know that Croy is a cautious, suspicious person because when Tally is using a saw to cut through wood, "Croy stood well back, poised to jump if the saw somehow slipped from her hands" (28.38). That's Croy—always prepared to get away from Tally because he doesn't trust her (especially when she's holding a powerful saw).
Even though Tally makes up a story to get Croy to relax, Croy still goes to David and spills his suspicions. As David notes, "From the moment you got here, he [Croy] was suspicious about your coming alone. He thought you must have had help along the way. City help. But I told him he was crazy" (29.46). So even David thinks that Croy is too paranoid. But, um, it's not paranoia if they're really out to get you. Right?
The last important person in the Smoke is also one of the few characters who doesn't get out alive.The Boss is the old (almost 40, whoa there, geezer) librarian. We get very little info about him—where did he come from, what surgeries did he get, what made him come to the Smoke, where did he get all his magazines? Nada.
But the Boss (and his library) does tell us all about the Rusty era. And the Specials also kill the Boss as he tries to "save a precious piece of human heritage from these barbarians" (33.32), which raises a serious question: what would we put ourselves in that sort of danger for? The Boss saves some magazines; and Tally will soon put herself in danger to save her friends. This would be an easy choice if our friends had magazines and we could save both at the same time. But what if we could take only one?