Nowhere in the strangely anachronistic world in which Penn lives will you find someone more unique than the boy called Klok.
Like Birdie, Klok came to the circus with a single name and no hint of his past life or biological family. (They call it running away to join the circus for a reason - people are generally running from something they don't want to be found by,) However, in this case, he was actually raised by members of The Show before he arrived at the train. Squint and Smolly, the train's engineer and his wife (both of who are under four feet tall) raised the boy alone until his was about ten years old. This was no easy feat, considering at sixteen he's bigger than most grown men.
Of course, there's one other huge difference between Klok's backstory and Birdie's. Klok's is pure cover-story. Rather than running away or being orphaned like most children of The Show, Klok was created without parents. Yes, created - as in android.
Built by Magnus Roma, and designed to look like Roma's deceased son, Klok is a spectacular creation. Strong, brilliant, and protective, Klok was everything the Warden's Commission was hoping for in the soldier they commissioned Roma to build... except he's also compassionate and capable of remorse. This "flaw" made him unsuitable for military service, and so Roma conspired with his friends Squint and Smolly to hide his "metal man" away where he couldn't be corrupted into the soulless killer he was meant to be.
Now Klok works as a stage hand, literally doing the heavy lifting for the circus as it picks up and puts down stakes for each performance. On the road, he becomes a valuable ally to Penn and her friends, which is a situation she finds uncomfortable given his appearance. She's known since she was a child that she's the one who killed her brother, so being followed by someone who looks so much like him is disconcerting. And given that he can only "speak" via text on a view screen where his voice box should be, she's forced to face her past on a regular basis - whether she can deal with it is another matter.