Zaktrak is a scared and nervous boy. He is independent and can be trusted to make good decisions in the absence of orders, but is principled and will not betray his own ethic, refusing to do violence.
He and Peg share a very close friendship.
Zaktrak got a job working as an engineer on Marielda's crosstown train thanks to a friend of his, an assistant of the Artificer Mundane who helped Primo make the train's navigation plates. Though he misses his family and the pay isn't great, he is happy to have such an important job and likes working with Peg.
Before Train Day, Zaktrak spent a night at a bar with Ethan Hitchcock, who he formed a bond of trust with, and Castille, who he told about the navigation plates. When The Six came and screwed things up for Peg and Zaktrak, the pair joined up with the crew, making sure that if they were going to lose their jobs as engineers that they'd at least get their cut.
A couple days after the heist, while Zaktrak was still learning how to get to The Six's headquarters from Emberboro, Zaktrak was followed by one of the Fontmen. Though he managed to gain the upper hand on them in an alley, Zaktrak couldn't bring himself to even knock them out, and was tailed to Chrysanthemum District, putting The Six on the Fontmen's radar.