The Banner of King Death!
The pirate flag was the Jolly Roger...a name of uncertain origin...known also simply as the Black Flag, or more to the point, especially among the pirates themselves as "the Banner of King Death".  The traditional design was a white skull and crossed thigh bones on a black background.  This was an old symbol of mortality, and not particular to piracy. In fact the pirates probably took the symbol from merchant ship captains who often drew the skull and crossbones in the ship's log to indicate the death of a crewman.  Other designs included a skeleton, dripping blood, or an hourglass, symbolizing death, violence and limited time.

They were used to terrify the enemy or victim, conjuring up fear and dread.  It was an important part of the pirate armory, and was the pirate's best form of psychological warfare, especially if combined with a reputation of not showing any quarter.

Sometimes two flags were used, the black and the plain red.  The Jolly Roger was run up first to indicate an offer of quarter.  If this was refused, the red or bloody flag was flown to signify that the offer had been withdrawn.

The flags depicted here are, with a few exceptions, authentic and were the flags actually used by real life pirates.  For edification of the story of Rafe Alexander and his fellow pirates, I have identified each flag with the corresponding ship in the story.  Where appropriate, the real pirate associated with that flag in denoted beneath, in parenthesis.

On a final note, I would point out the Black Widow's flag was designed by myself.

The Devil's Claw...Rafe Alexander
The Viuda Negro...The Black Widow
The Cutlass..Sam Newell, and Robert Sands
The Deliverance...Capt. McDonie       (Bartholomew Roberts)
The Fancy...Capt. Sloane 
 (Henry Avery)
The Wydah...Capt. Custer  (Walter Kennedy)
The Rising Sun...Capt. Belcher  
(Callico Jack)
The Ranger...Capt. Coffey
  (Emmanuel Wynne)
The Flying Dragon...Capt. Pratt  
(Edward Lowe)
The Revenge...Capt.Bailey  (Stede Bonnett)
The Pearl...Capt. Tew
The Royal Fortune...Capt. Powell
The Queegah... Capt. Outcalt and 
Capt. Joe Burke
( Black Bart)
The Adventure Galley...Capt. Moores
The Liberty..Capt. Freeman
The Greylock...Capt. Green
(Walter Kennedy)
The Whisper...Capt. Murphy
(Christopher Condit)
The Viper... Capt. Serey
The Demon...Capt. Simmons
The Diablo...Capt. Brunty
(Thomas Tew)
The Vampyre... Capt. Griffin
The Sea Witch... Capt. Welch