Though numerous similar creatures exist throughout mythologies worldwide, Sirens have their most famous roots in Greek mythology and Germanic legend.
Some of the Greeks believed in the existence of only two (Aglaopheme and Thelxiepeia); others believed that there were three (either Peisinoe, Aglaope, and Thelxiepeia, or Parthenope, Ligeia, and Leucosia), while others thought that five existed. And still others believed that there were as many as thirteen (names varying as Thelxiepeia/Thelxiope/Thelxinoe, Molpe, Aglaophonos/Aglaope/Aglaopheme, Pisinoe/Peisinoë/Peisithoe, Parthenope, Ligeia, Leucosia, Raidne, and Teles). Their parentage also varies. Some designate their father as being Phorcys (a sea deity who was also the father of the original Gorgons and numerous other monsters and sea creatures), while others say that their father was Achelous (a river deity). Their mother is often said to be one of the Muses (Terpsichore or Melpomene), or a nymph (by the name Sterope) or the Earth itself (Gaia).
The Germanic Siren, however, was singular. She went by Lorelei (also spelled Loreley); sometimes she was similar to the Sirens of Greek myth, while other times she was the spirit of a jilted woman pining for her long-lost lover. Sometimes, she was even said to be an invisible spirit whose voice was the only thing that remained of her after passing, similar to the Greek myth of the nymph Echo.
One thing that the Greek and German mythos share, though, is the capability of a Siren to produce a song so lovely that, as sailors steered off course, attempting to reach the warm embrace of their assailants, they would be lured to a brutal death on the rocks of the island where the seductive songstresses resided. For the Greeks, that island went by the name of Anthemusa/Anthemoessa; for Lorelei, it was an immense rocky cliff which was named in her honor after her demise.
Due to their heritage, they are supernaturally beautiful. They are most often blonde (though other hair colors are possible—even those considered unnatural to other humanoids). In the same way, they vary from lithe and sylphic to voluptuous and buxom in figure. What's more, some appear like normal human women; others have wings, others have a bird body from the waist down, some have a hybrid avian-woman body, and still others possess a fish tail in the place of any legs at all. Skin color also varies, as do the eyes (some have even been known to have turquoise skin, or pitch black eyes like a shark—perhaps a supernatural indication of their insidious nature).
A siren is always a charming and seductive being to encounter. They will never be caught with a "bad hair day" and don't require all the tedious upkeep of the average woman. They are dainty and demure without trying, while alluring and sexually attractive all at the same time. They are masters at the art of persuasion and enticement, knowing exactly what to do or say to get a man all hot and bothered. Naturally, this makes them the bitter rivals of mortal women. Though they refrain from physical combat or other physical shows of hostility (which would detract from their apparent charm and femininity), they often clam up, or even flee in a disdainful huff, at the mere sight of a woman (a behavior which gave way to the ancient Greek practice of not letting women board their ships, even as company on long voyages).
As for hierarchy, they are often born in groups called "choirs", which stay together for their entire lifetime; the eldest sister often has the most enchanting voice, and as such, is the leader of the choir. If ever such an occasion arose, they would never allow another siren to join their choir, nor would they be expected to attempt joining another choir if, for some reason, their former one were to disband.
If ever a siren must leave her sisters (such as the death of her choir, her own impending death, pregnancy, or banishment), she often elects to go off on her own island (or other secluded area) and conduct business as required. Otherwise, a siren is not expected by her sisters to ever leave the choir.
- Siren Song: They are naturally gifted with a knack for temptation and arousing desire. However, they are most famous for their "Siren's Song", a beguiling melody which they use to lure sailors to their deaths, on the rocks of the Sirens' home shores. The intriguing melody itself, combined with a Siren's all-too-tempting lyrics makes the song a ready snare, but for some reason or another, it works only on men (while women won't even hear it at all). With that song, some call out to their target's passing ship to entice them with promises of untold sexual ecstasy.
- Longevity: Aside from their incredibly long life span, they possess, from birth, an ageless beauty and witty charm that a mortal would describe as nothing less than hypnotic.
- Supernatural Knowledge: Though, others claim with the tempting tune, that they could reveal the supernatural knowledge they'd gained from the divine; knowledge of the fate of the world, of business, of the sciences, of the future, of the past…if that sailor would only drop by and stay a while.