Just finished it yesterday, the central characters are a pretty tight group. Zara, obviously, the 'Dark Lady' herself, runs this sprawling, dangerous network from the shadows—she's not a traditional hero at all, more of a necessary evil type who does genuinely awful things for what she sees as the greater good. Then there's Kael, her second-in-command and sometimes lover, whose loyalty is constantly tested because he carries the moral compass she seems to have sold off. Honestly, their dynamic is the whole engine of the book for me; it's less about the schemes and more about whether he'll finally break and try to stop her.
Emmett, the young scholar she basically kidnaps to decipher some ancient texts, provides the outsider perspective. Through his eyes, we see the horror of her operations up close, but also their weird, twisted necessity. His role is mostly to ask 'but at what cost?' over and over, which gets old fast, but his knowledge drives the plot forward.
I found Leon, the rival crime lord, kinda underdeveloped. He's mostly there to apply external pressure and show that Zara's methods, while brutal, might be more effective than his old-school brutality. The roles are clear, but the novel's strength is how it blurs the lines between them, making you question who's actually right.