I'd say Luthen and Kleya have a father/daughter relationship in which the daughter has long since eclipsed her aging father. She still respects Luthen for showing her the ropes, and Luthen is nominally in charge of their "family business," but Kleya's the one propping up the operation. He's the face of the conspiracy, but she's the one handling all the logistics.
Just compare the number of times Kleya gives Luthen instructions to the number of times Luthen gives Kleya instructions, and you'll see she's the one making most of the decisions. In fact, the one time we see adult Kleya awaiting Luthen's instructions, she's just told him what instructions to give her: "Tell me to shut it down." And even though Luthen's technically in charge, he issues the exact instruction Kleya told him to issue.
Kleya defers to Luthen because he's her father figure and her coconspirator, but by the time Kleya's an adult, I don't think she sees him as a mentor anymore. Their operation has become so far-reaching, of the two of them, only Kleya can follow it anymore. She knows more about what's happening on the ground and she makes all the important decisions.