Lacewing

From the Steampunk world of Vaesanum, the first book in the Ellum Cycle. 

Mordecai Ellum is no stranger to violence. He found it in his former work as an officer of the law. He perpetuates it now as a duelist-for-hire. While he hopes to retire and stop fighting, he remains a violent man.

When physician Ruth Amni hires Mordecai to help rescue her parents from a government black site, he sees it as the chance to leave his life behind. Instead, he faces a host of new threats:

A suspicious release of human-like machines.

Government corruption.

An ancient language with mystical abilities.

In these confrontations, Mordecai must decide the kind of life he wants. What would he be without violence as his identity?