Lyra Vex

This wealthy madame is a black widow - she dates wealthy men, marries them, then kills them for money. She has never been caught, and worked her way all the way from Quaddari to Riverrise. She's currently on a date with Silas Thorne, who also has amassed a fortune by marrying wealthy heiresses who go missing by his hand. They are both plotting to kill each other, but don't realize the other is working against them yet. She's brash, rude, and has a deeply funny sense of humor about death and dark subjects - she often jokes about death in a way that hints how serious she is.

She's stuck with Silas, who she can't get killed. She's volunteered them both to be conscripted into the volunteer army in an effort to get him killed.