Mu-otts
A sapient race of small, peaceful fish folk who dwell in rivers, particularly the Illusarnae. Roughly humanoid and upright-standing on their flattened back fins (they have no legs), they are plump and wide-mouthed, with large, black eyes, no teeth, and small fins where ears would be. Their scales are usually brown or green with white bellies, and their fish-like heads face forward like a human's.
Primitive and reclusive but friendly, mu-otts have been known to aid and trade with travelers and fishers. They themselves eat shellfish and water plants. When forced to defend themselves, they fight capably with harpoons and nets. The most powerful among them are Druid and Cleric. Monk and ranger are not unknown among them. One of the few well-known mu-otts is Skup.
Mu-otts rarely wear clothing other than belts and pouches, and live a mostly nomadic life. They travel the length and breadth of their rivers looking for food. When they do settle in one place, they build dwellings under the river floor. Usually they live in clans of a few hundred, mating and trading with other clans. Clans are always democratic, with an elected chief. When mu-otts venture onto land it's usually to trade or go on adventures, which most mu-otts try at least once. Most mu-otts worship Raketra.
Most Mu-ott mothers give birth only once (though they pair for life), to a clutch of 2d10 eggs which hatch after six weeks. Mu-otts usually have only one name, which is unisex and describes the parents' first impression of the young one as it hatches. Examples include Quip (Fast), Wuus (Brighty-Colored), Poom (Powerful), Yupe (Determined), and Zoont (Dark).
Mu-ott PCs
Ability Score Increase: Mu-otts are tough and hardy, and also attuned to their environment. Your Constitution score increases by 2, your Wisdom score increases by 1.
Age: Mu-otts are short-lived, reaching adulthood at 2 and living for as much as 30 years.
Alignment: Mu-otts live mostly in isolation in their rivers, rarely coming on land or involving themselves in the affairs of the world, but are naturally gentle and good-natured. Most are Neutral Good, they are seldomly Lawful.
Size: Mu-otts stand and walk, when not swimming, on their shorter back fins and use the longer, more articulated side ones as arms and hands. They average about 3ft. tall and average 50 lbs. Your size is Small.
Speed: Mu-otts have a walking speed of 25 ft. and a swim speed of 30 ft.
Riverborn: You can breath air and water, and have Darkvision of 60 ft. You are proficient with nets and harpoons.
Slippery: Due to your slick scales, creatures have disadvantage on checks or attacks made to Grapple or Restrain you.
Well-Padded: You have resistance to Cold damage.
Languages: You speak and understand Common Tongue, Aquan, and Mu-otts.
Names: Mu-otts usually have only one name, and make no gender distinctions in naming. Examples: Yut, Trun, Padt, Uul, Siim, Oto, Yun, Drebt, Ploo, Wek, Gwep, Wundt.