One of my favorite things about our Sea Princes campaign has indeed been the use of factions, particularly pirate fleets which I became keen to expand upon when I saw the Crimson Fleet in the Dungeon Magazine AP, Savage Tide. Here is a survey of some known pirate fleets that ply the seas of the Flanaess. I leave much of the intricacies of these groups to each individual DM for now. Enjoy, mateys!
Prince's Fleet (large fleet)
Home Port: Monmurg (Sea Princes)
Rivals: Toli Armada, Blue Confederation
Enemies: Crimson Fleet, Keoish Navy, Ulek Navy
Overview: This fleet is comprised of those nobles and captains loyal to the Prince of Monmurg who is generally regarded as the ruler of the entire Hold of the Sea Princes. These captains adhere to the laws of the sea, showing mercy to foes and eschew slavery in principle though its practice is too widespread in the mainland Hold to stop presently. The Princes Fleet is the main bulwark against the Keoish Navy and the Lion Throne retaking their former province back. For this reason, their piracy is subdued, now more focused on economic diplomacy.
Toli Armada (large fleet)
Home Port: Port Toli (Sea Princes)
Rivals: Prince's Fleet, Sasserine Fleet, Crimson Fleet
Enemies: Keoish Navy, Ulek Navy
Overview: The pompous Prince of Port Toli commands the loyalty of many captains in the southern Hold who are more concerned with personal wealth and prestige. This fleet is mainly responsible for the nation's exploration and expansion into the jungles and islands farther south, as well as the slave trade so despised by Monmurg. The Toli Armada is a fearsome naval power in its own right, but is prone to alliances and defections to the Crimson Fleet much to the dismay of Monmurg.
Hold Flotilla (small fleet)
Home Port: various (Sea Princes)
Rivals: Princes Fleet, Toli Armada, Sasserine Fleet
Enemies: Crimson Fleet, Keoish Navy
Overview: This is a loose association of captains who consider themselves above the petty squabbles of the Hold nobility and their fleets, preferring to seek independent ventures legitimate or otherwise. These captains tend to stay close to home waters however, until such time when the entire Hold is threatened. In these emergencies the Flotilla rallies and its squadrons sail with the flags of their kin.
Home Port: Scuttlecove (Pirate Isles)
Rivals: Toli Armada, Cousins of Tilva
Enemies: Keoish Navy, Prince's Fleet, Hold Flotilla, Iron League, Ulek Navy, Sasserine Fleet, Duxchan Armada
Overview: The dread Crimson Fleet carved out an island realm of their own in the seas south of the Olman Isles. The rulership of this fleet and their diabolical patrons is highly questionable. What is known is the Crimson Fleet attracts all manner of cutthroats, mutineers and disaffected captains who have no where else to call home. For this reason, the Fleet is a mish-mash of former pirates from nearly every known fleet in the Flanaess. Crimson Fleet pirates are accepted bounty in nearly any port in the south seas.
Home Port: Kro Terlep, Ekul (Tilvanot Peninsula)
Rivals: Slave Lords, Blue Confederation, Crimson Fleet, Duxchan Armada
Enemies: South Provincial Navy, Iron League, Rel Astran Navy, Sea Barons, Sulward Blockade
Overview: This coalition of pirate captains seem to control all harbors, coves and islands surrounding the coast of the Tilvanot Peninsula and the horn of Hepmonaland. Their presence is both a bane to trade-fleets on the Azure and Aerdi Sea and a boon to the poor, defenseless villagers of this tropical region whom give the Cousins shelter. The captains of the Cousins are without exception always of Suloise descent though their crews are accepting of any ethnicity or race. They are considered more honorable than most of their rivals and have been known to sail far out of their normal sea-lanes on business for the mysterious plateau realm of Shar, rumored to be their true masters.
Slave Lords (medium fleet)
Home Port: Elredd, Highport (Wild Coast/ Pomarj)
Rivals: Blue Confederation, Cousins of Tilva
Enemies: Hardby Marines, Iron League, Nyrondal Navy, South Provincial Navy, Dyvers and Furyondy Navy.
Overview: The infamous yellow sails of the Slave Lords have long been feared in the central Flanaess, though their vicious captains rarely realize the identities of their true masters. The presence of these pirates is a constant concern for Wild Coast towns and merchant fleets crossing the Woolly Bay. Less obvious is this fleet runs a slaving network that has somehow spread inland to the Nyr Dyv incurring the wrath of the Dyvers and Furyondian Navies. The Slave Lords have also sought to expand their fleet by training Pomarj orcs and goblins the ways of sailing, to limited success.
Blue Confederation (medium fleet)
Home Port: Blue (Pomarj)
Rivals: Slave Lords, Iron League, Prince's Fleet
Enemies: South Provincial Navy, Hardby Marines, Ulek Navy, Nyrond Navy
Overview: The alliance of independent captains who mainly harbor in the coves of the southern Pomarj and Blue pre-date the rise of the Slave Lords and have managed to remain viable by working with them to harass all merchant activity passing through the Sea of Gearnat. Even so, the Blue Confederation is generally honorable compared to most pirates, and has also been known to smuggle for the Iron League if it means affecting the South Province.
Densac Squadrons (small fleet)
Home Port: Narisban (Olman Isles)
Rivals: Crimson Fleet, Prince's Fleet, Cousins of Tilva, Toli Armada
Overview: The captains who call the Olman Isles their home are a mixed bunch of retired fleet captains, Olman-born sailors and Narisban freebooters. The Densac and the port of Narisban is traditionally considered neutral waters for all pirate society and the Densac Squadrons are merely an informal alliance to protect their routes. Foreign explorers and traders seeking riches to the south are not so safe.
Sulward Blockade (large fleet)
Home Port: Sulward (Lordship of the Isles)
Rivals: Rel Astran Navy, Duxchan Armada
Enemies: Sea Barons, North Provincial Navy, Spindrift Isles, Cousins of Tilva
Overview: The Sulward Blockade is formed by captains sworn to the Lord of the Isles who is nominally a member of the Iron League as well. The captains of Sulward, once part of the Great Kingdom, have changed from their piratical ways to extracting tribute on all Aerdian vessels passing south to the jungles or through the Tilva Strait (Iron League vessels pay none). In particular the Oerid population of this fleet has made them biased towards most Aerdian ships unlike their islander rivals the Duxchan Armada. The Sea Barons however, desire to crush the blockade someday and with it, retake the Isles.
Duxchan Armada (large fleet)
Home Port: Duxchan (Lordship of the Isles)
Rivals: Rel Astran Navy, Sulward Blockade, Cousins of Tilva
Enemies: Sea Barons, North Provincial Navy, Spindrift Isles, Crimson Fleet
Overview: This fleet is comprised of mostly Suel-born buccaneers from the southern isles of the Lordship. These captains are more free-wheeling and prone to adventure than the reformed Sulward Blockade, but are quick to rally in times of war. The Duxchaners have been in open conflict with the Sea Barons for a long time and chafe at contested sea traffic in the Tilva Strait with the rival Cousins. The Duxchan Armada is highly honorable and often take part in dangerous Iron League missions against the Aerdy for the riches and glory.
Home Port: Soull, Krakenheim, Glot (Snow, Frost, Ice Barbarians)
Enemies: Sea Barons, North Provincial Navy, Hold of Stonefist
Overview: The raiding captains (often chieftains) of the Thillonrian Peninsula are far flung from the cares of the south and central seas, but they share a generational hatred for the provincial navies of the Great Kingdom of Aerdy. When not raiding over the Icy Sea or venturing to places uncharted, these barbarian ships come into conflict with one another for plunder rights on the Solnor Ocean. Even so, the raider-kings of Rhizia can at times overcome these tribal differences to form a mighty invading fleet.
Added notes on national fleets for completion sake:
The Great Kingdom of Aerdy has a considerable presence on all the seas, being comprised of the North (medium) and South (large) Provincial Navies and in addition the formidable Sea Barons (large).
Rel Astran Navy (medium) protects the port and merchants of this free-city and have little love of the Aerdian Navy or the Sea Barons.
The Iron League Fleet (large) is comprised of ships from Irongate, Onnwal, Idee and Sunndi (the Lordship has its own fleet). Irongate and Idee have the strongest warships, while a majority of the fleet is tiny ships converted for war.
Keoish Navy (large) and Ulek Navy (small) are the allied fleets of the western kingdoms and principalities that trade on the Azure Sea.
Nyrondal Navy (medium) is mainly concerned with piracy across the Sea of Gearnat, but also in helping the Iron League vie against the Great Kingdom.
Spindrift Isles (Lendore Isles) Navy is mainly composed of elven warships whose speed and skill have confounded all pirates and navies on the seas. Only the Duxchaners have been foolish enough to test their mettle and sail within their waters.
Sasserine Fleet (small) captains serve council-members of the free-city nestled on the Jeklea Bay coast near the Hellfurnaces. They maintain peaceful ties with their former rulers the Sea Princes, but often defend against Crimson Fleet raids.
Dyvers and Furyondy Navies (medium) control the western freshwaters of the Nyr Dyv. Their main concerns are the threat of Iuz, deep lake monsters and smuggling Rhennee. The infiltration of the Slave Lords has been an added thorn in their side.