Strength in Numbers...
Night.
When the sun goes down, and the moon and stars come out to play, people tend to disappear into their respective abodes.
They sleep it away in preparations for the dawn, or stay indoors where it's warm while gazing at the darkened sky, but all the same, they tend to ignore the comings and going of those that go bump in the night. Granted, many who do move about in the night tend to do so swiftly and quietly.
Tap, tap, tap.
Upon the rooftops of Pearl Tusk Harbor, figures cloaked in black, donning masks of a deeply shaded blue leaped from place to place, out of sight and out of mind for a majority of folks, save some savvy few who didn't wish to attract unnecessary attention.
These nimble warriors in black were known as simply "shadows", the lot of them served as the main intelligence/assassination units of an international organization to which one "Fia" Venus reported to.