Sirens are one of the more notorious avian races; stories have been told for generations of mariners tormented by songs of haunting beauty, calling them irresistably to their doom upon rocky outcrops and reefs. Whilst many of these reports are the result of old wives' tales and hearsay, the abilities of most Sirens and their often callous attitudes certainly lend credence to such tales. It is believed that nearly 10% of their remaining population - some 250 or so Sirens - have wound up in the employ of Destiny's Call.
Physically, Sirens are the most human-like of the avian humanoids - possessing the head and torso of an attractive human. They possess feathered wings and hawk-like tails, and each possesses a prominent feathered crest which differs in size, shape, and coloration depending upon the individual Siren. A Siren's long legs are feathered at the bottom and possess long, scaled digits tipped with razor-sharp claws, rather similar in appearance to an Osprey. Their backs are often covered in small feathers. Older adults tend to have more feathers on their legs. The most common colors for their feathers are brown or gray, but black and white are also known to exist. Striped or splotched patterns can occur amisdt their feathers and are considered a sign of good fortune. Females tend to be a little taller, larger, and heavier than males. Due to their hollow bones, they tend to be relatively lightweight. A Siren lives for about 300 years on average, reaching maturity at about 17.
Magically-gifted, naturally capable of flight, and with innate abilities to influence others, Sirens are predominantly known for their capricious and often self-indulgent attitudes; many feel their magical abilities and singing abilities gives them the right to do whatever the hell they want by right, whilst others are more gentle-natured and simply free-wheeling and carefree. Regardless of which mindset a given Siren perscribes to, however, one common thread unites them - their race is slowly dying out.
Under normal circumstances, Sirens are genetically homospecies, but genetic mutability on the part of several other humanoid subspecies gives them the ability to inter-breed with them - this trait was falsely believed by many Sirens to be useful, since female Sirens outnumber males by roughly 1.5-to-1, and the natural hardiness of humans (and susceptibility to the Sirens' abilities) made them prized mates. Unlike other races with similar traits, however (such as the Viera), this incorrect assumption has resulted in increasingly-few Siren eggs being viable - on average, only one in about 20 will hatch. The genetic damage due to Siren interbreeding has been incalculable, and, paired with fatalities bought about by those who hate and fear them, there are now fewer than 3000 Sirens in the world. Making matters worse, male Sirens account for only about 30% of those remaining. A secondary cause of their population decline is that as a rule, their species has general tendency to view themselves as superior to all other creatures, openly using their abilities to amuse themselves at the expense of other races - a facet of them that has caused many Sirens' lives to end in violence.
Sirens have an innate proficiency with wind and/or water magic (it varies in strength and element depending on a given Siren), and are particularly feared for their singing abilities. A Siren's song can cause all who hear it to become completely beguiled, moving towards the Siren in as direct a route as possible - even if said route pulls them into obvious danger, such as off a cliff or through a fire. A beguiled victim that reaches a Siren during her song will simply stand where they stand, transfixed, and generally offers no resistance to the Siren (even if she chooses to attack those she lures in). Worse, many Sirens can make a suggestion to a creature captivated by its song (limited to a sentence or two), playing upon a creature's vulnerable mental state in order to get the affected creature to do as the Siren wishes, even after the song ends. Several Sirens have become adept at using this ability insidiously. Fortunately, Sirens cannot sing for very long; their captivating songs are draining for them to use and sap their reserves of magical energy, ergo only allowing them to use it in short bursts (2-to-3-minutes). Additionally, it only lasts for as long as the Siren actually sings; creatures still around when one of their songs is ended (often by force) snap out of their trance in a matter of seconds - and are likely to harbor a serious grudge.
Sirens are distantly related to Harpies, but have not been as skilled at survival as their more-primitive kin. They are considered a case of divergent evolution; whereas Harpies evolved in the mountainous regions in and around Eulitracia, Sirens evolved in more aquatic regions. It is extremely likely that the two species share a common genetic ancestor as a result. The two species can interbreed, but the results are generally unstable.
Siren culture is not terribly far removed from their Harpy cousins in that it is fairly amoral by modern standards; the primary difference is that Sirens, being less-numerous and smarter, trend towards being more nuanced. Sirens in DC tend to be very disciplined, for example, but the ones outside trend towards being much more anarchic and generally chafe under authority. Few of them actually respect creatures that can't resist their singing; in their eyes, someone controllable is someone to dominate and use, whilst those who can resist (or better yet) sing themselves are those who rule. This mindset is very common in most Sirens, and is clearly visible even in the most affectionate of them; Monique, for example, tends to mercilessly pick on the likes of Athena, despite not really having much reason to, and has been known to encourage Red to flirt with certain people for much the same reason. In the wild, Sirens have a very specific pecking order, with an Alpha female leading individual flocks. This behavior carries over to Sirens in a military setting, with ones in charge of a large number of personnel often being such a Siren via necessity.