Elemental, Water

 The water elementals in the bestiary include living waterfalls, quatoids, tidal masters, brine sharks, and elemental tsunamis. Most of them are either penalized for not standing in water, or have abilities that benefit from being in open water. While you *can* stick one of them in a pool and have your players surprised and scared, encountering these in the open sea (or, you know, on their home plane of water, that is... all water?) makes for so much more drama.

The Untari jungle is known for its many streams and waterfalls, but any attempt to map their locations is futile, as they appear to be changing places. Indeed, the jungle is a place of thinning, where the material plane meets the plane of water, and the many living waterfalls who keep crossing over find it very fun to move the streams and rivers around. However, they are very shy and secretive about it, and if mortal eyes see them in action, they might grow violent.

The Angulii pass, a stretch of sea between Northlandia and the polar ice caps, is known for its treacherous waters. Many terrible aquatic beasts lurk here, but among the most feared are entire schools of brine sharks. These elementals are said to jump dozens of feet up into the air, dragging sailors with them and plunging them into the cold depths of the ocean. Some of the more experienced sailors claim that offering them fresh water might keep them off - while others dismiss it as dangerous and wasteful superstition.

The Blue Brothers were the twin tidal master guardians of Akhtana Archipelago. One day, a group of small, octopus looking elementals appeared and whispered something into the brothers' ears. The brothers immediately nodded and then left into the deep, never to be seen again.
As the Calamity, an elemental tsunami that visits once every fifteen years, approaches, the islanders must choose: will their strongest and most capable try to stand against the Tsunami themselves, or shall they go on a quest to try and find their lost guardians?