The Shadow Quartet is a group named by several high ranking marines as dangerous and utterly destructive. Its a nickname given to the traveling people Brandon Note, Thomace Billow, Brickar and Larden Floyd. Their existence is said to be futile for the New World and they are mentioned to have great skill. Their objective is to become widely famous, already've done so. The group was established on Barmount Island, and they quickly became a pirate crew after meeting Meldin Horn. Together they defeated Doma and McGuy, establishing a reputation as pirate crew.
For further information, see Blackcloud Pirates.