River Maidens

"One of the Terrestrial Spirits."Ribbon fin frills, nimble serpentine tail, a sparkle in the water below. The River Maidens are ancient creatures believed to be protector spirits of the woods. They take the form of humanoid women from the waist up and an aquatic snake below, allowing them to swim through the waters with ease.

Legend
One of the many types of Wardens, known mostly by sailors and fishermen. The lengthy voyages of old wind-powered vessels lead to extended times away from home, and even the most stalwart seafarer can feel the twinge of loneliness.

Despite the many accounts of encounters with River Maidens, they still remain a myth among human settlements. Elusive and timid, these half-human spirits have been said to save drowning sailors fallen overboard in storms, only to release them on shore with an article of clothing missing. Other legends speak of a lonely widower living by the sea with a mysterious woman he visits via rowboat. Some stories claim that the River Maiden is the one who caused the storm in the first place, or that they use their alluring voices to cause a ship to wander astray and become lost, but these are in the minority.

Description
The River Maidens are fairly varied in appearance, though most take on the shape of a serpent from the waist down. Very few have a more fish-like appearance, or are said to be mimicking the form of a seal below the abdomen, but it's not clear if these are just a rarer variant or another type of creature altogether. In addition to their scaled lower halves, River Maidens have the noticeable tell of fin-like ears, which- even in stories that include mention of disguising themselves temporarily as humans- they are still said to display, often leading to their eventual discovery.

Capabilities
River Maidens are one with the waters through which they swim, and can merge with and reform from it at any moment. They have control over the waters that they are possessing to a supernatural degree, able to control not only the currents and temperature but also the magical properties of it. This can include enabling people to breathe underwater and to instill a rejuvenating effect within a small area. Waters inhabited by a River Maiden can endow increased recovery time to anyone who soaks within them, assuming she is willing to help.

Beyond their control over water, River Maidens also manifest the shared capability for magical singing as the rest of the Warden types. Their particular style of song is 'the Ocean Hymn' which works very similarly to the World Song of their forest kin, with a few differentiating factors. In addition to the emotional inspiration that their singing can rouse, the soothing nature of their voice can touch deep within the listener's psyche and untangle the twisted anxieties of a traumatized mind.

Weaknesses
One of the few sure ways to harm a River Maiden is the use of electricity against the waters in which they dwell. Lightning storms can be dangerous for sailors but they are also a sign that they won't be disturbed by any underwater denizens. Aside from that, the River Maiden requires moisture in order to survive, and thus can't live on land for any appreciable amount of time. Some are said to be capable of taking on human form for short periods, but even then they must drink plentiful water to stay hydrated, and prefer to return to their river or ocean as soon as possible.