Generally speaking, the Nautiloidea, a race of which Ness is a member of, are considered to be pretty spineless. They tend to live out their lives in the deep oceans of their homeworld, only venturing to other worlds if their supplies of food and other necessities run low.
The same cannot be said for Ness. Ever since a young age she has been wandering the vastness of the universe in search of masters who would teach her new combat skills. You can often hear people say that she visited 20 000 world, learned to use 100 000 different weapons and mastered 50 000 fighting techniques. All of these are, of course, understatements.
Fulfilling her lifelong yearning, she decided to form a pirate crew wanting to become (in)famous across the galaxy. She believes that the stark difference between the freedom, that she and all other pirates enjoy, and the cowardice of her own species would stir up some emotions in her people and they would once again venture out into the vast, unknown, universe. This, she believes, is the true destiny of her species.