Asrai are water spirits from the celestial River Oceanus of the Upper Planes in Planescape. They work mischief in the shadowy waters of the night there.
They are a hazardous exploration encounter, though not much of a direct combat threat.
In the dark water before you, a group of tiny creatures cluster, like a school of fish, each one with long, golden hair that shimmers in the starlight.
Creature (Fey): Asrai, like most fey, are more interested in their own amusement than they are in other creatures, and have an initial reaction of Unfriendly. Its attitude can be improved with a Charisma check (DC 12).
An unfriendly asrai (pr one playing a prank) may use their hair to hypnotize a creature that fails a Wisdom save (DC 10). An asrai may lure a victim who fails their save over the edge of their boat or bridge — the hypnosis causes a creature to move up to their speed in a direction the asrai chooses. The asrai can continue to lead people astray as long as those people keep failing their Wisdom save.
A hostile asrai may bite at +0 for 1d4 damage, or they may try and riddle a victim with arrows at the same bonus for 1 point of damage. The arrows are smeared with fish guts, with inflict disease on a creature struck by them.
Ability Scores: Str 04, Dex 11, Con 03, Int 10, Wis 12, Cha 14
Vulerabilities: Asrai cannot survive in sunlight: exposure to direct light will cause them to melt away if they fail a Constitution check (DC 10, +1 per round of exposure).
Associated Creatures: Asrai are accompanied by sharks, giant pike, and other predatory fish — the asrai isn't allied with them, but the fish come to prey on those hypnotized and who fall into the water. The asrai ride dire flying fish, but otherwise travel in small schools.
World: Asrai are celestial water sprites, as untamed as the depths. They may appear in mystical places in the mundane world, or can be found by those exploring the heavens in greater abundance.
Story: Asrai add mystery, beauty, and a bit of danger to any expedition on a body of water. They are not overtly hostile, so the potentiality to ally with them can be employed to relay information as well.
Mechanics: Asrai are mostly a threat for characters with a low Wisdom score, who may wander into the jaws of some predatory fish. Still, they are not strong creatures, and are best employed with other hazards for a true challenge, or treated as set dressing otherwise.