Siren

Physical Description

Sirens commonly appear as an amalgamation of a beautiful woman and some form of sea life; typically, they acquire features such as fins, claws, gills, and tails, and wield these features as natural extensions of their own bodies. Some have even been known to possess wings, a trait reminiscent of seafowl, but one used to deadly effect. There is nothing so terrifying as the sight of a siren soaring downward, snatching their entranced victims from the decks of their ships.
Sirens are long-lived, having lifespans documented as long as 500 years in some cases. In addition, sirens are fiercely intelligent, to the point that they are able to speak and comprehend most known languages. Given their lack of socialization, cryptozoologists theorize that their do not communicate with their tongues, but instead with their thoughts; that a siren's song is not a physical one, but instead a manifestation of their desire, projected across the ocean's waves as a form of magic.
Sirens are not exclusively female, despite most mythology depicting them as such. They procure mates in much the same way as they hunt: by entrancing the object of their desire and taking advantage of the hapless victim. A siren's mating dance is a long, drawn-out process; most victims do not live to tell of the tale, as the intelligence and viciousness of a Siren is comparable only with their cardinal sin of obsession.
They tend to nest along rocky outcroppings bordering the ocean, although industrial expansion has forced them further into the ocean, relegating them to distant islands, coastal caverns, and the borders of undiscovered lands.

Society

Sirens have very little contact with one another, preferring solitude and uncontested hunting grounds. When sirens do cross paths, they are almost inevitably drawn to fighting; whether this is due to a desire for food, or whether it is born of mutual jealousy, one will eventually overpower the other with their song. If the victim is not slain, they will instead be controlled, assuming a puppet-like disposition until they eventually waste away; additionally, their power will be drawn into the victor, increasing the power and range of their song.

Siren Traits

Ability Score Increase. Your Constitution, Wisdom, and Charisma scores each increase by 1.

Age. Sirens have relatively long lifespans. They become physically mature at 20 but can live up to 500 years naturally.
Alignment. Neutral, leaning towards evil. Sirens tend to have obsessive personalities, and the ease of using their Call is a temptation that many fall to.

Size. Siren's vary in height and build, from just over 5 feet to just under 6. Your size is Medium.

Speed. Your base walking speed is 30 feet. Darkvision. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern colour in darkness, only shades of grey. Amphibious. You can breathe both air and water. Siren's Body. As a bonus action, you turn into an amphibious form, your legs becoming a single powerful tail. Your walking speed is reduced to 5 feet and you gain a swimming speed of 40 feet. While in this form, you can use your bonus action to return to normal.
Call. Sirens are known for luring people and beguiling them. Whenever you make a Charisma (Performance) check to sing, you are considered proficient in the Performance skill and add double your proficiency bonus to the check, instead of your normal proficiency bonus. In addition, You know the friends cantrip. When you reach 3rd level, you can cast the charm person spell once and need to finish a long rest before you can cast it again. When you reach 5th level, you can also cast the suggestion spell once and need to finish a long rest before you can cast it again. Charisma is your spellcasting ability for these spells.

Charm Resistance. Have advantage against being charmed, being a skilled charmer yourself.
Languages. You can speak, read, and write both Common and the Primordial dialect of Aquan.