From The Human Clans
The people of Shark Clan are warriors and sailors that dwell in the seas of the Qi Province. They are also rogues -- pirates, that make their living by attacking other ships and stealing their goods. Little is known of Shark Clan, for historians are not exactly welcome among them. All I can say is that if you sail upon the Reshal Sea and are approached by a ship with a shark's flag, you would do well to pray to Lemicus for safety.
Shark Clan is widely conflated with the Red Sash Pirates (who are also known as just 'the Red Sash') by outsiders, but this is not really correct. While some Shark Clan members do join in with the activities of the Red Sash Priates, the Red Sash is an entirely distinct group from the Clan.
The Red Sash is a group of pirates operating in the Reshal Sea. Historically composed of and led by humans, it is presently led by Aedem, an elf, in the aftermath of the death of Sallador, a human. Aedem had joined the pirate group shortly before becoming its leader, previously being known as an independent operator.
The group had (ca. 2002) been dormant and thought dispersed before a series of attacks that eventually culminated in wide-ranging attacks during the Outcast War.
Long ago, the group was just known as the Sashes, and was a small Human organization (not quite large or formal enough to be considered a true Human Clan) like many others, though preferring to roam the seas rather than stay on land. Group members wore sashes to distinguish themselves by rank and position. Leaders wore purple; warriors, red; and merchants and other wore other colors, such as yellow, blue and green. It is believed that their society fractured in some way, as red sashes predominate greatly nowadays. 
- GM Jaedren on the forums, 7/6/2011, and GM Persida on the forums, 4/13/18