Bangladesh DuPree likes working for Wulfenbach, because Klaus knows the value of her talents and pays her well. There's not nearly enough killing to satisfy her most times, but every once in a while, he lets her really cut loose and have fun.
He even let Bang hand-pick the crew for her personal airship. She picks only the most bloodthirsty ladies for lieutenants, the most promising killers for her crew.
Someday she'll kill Klaus and take her new crew on a glorious killing spree across Europa, as a pirate queen once more. But in the meantime, the pay is good...