Karoo, or desert mermaids, as they are more commonly live in and around a desert oasis. They resemble mermaids of legend with an upper torso and body like a human, but instead of a fish-like lower half, their body is more snake-like. Their skin is tan, gritty, and rough like sand, and their hair is usually long, thick like braids.

Karoo live around desert oases and protectors of the ones where they decided to settle down. They will observe travelers to their oasis, and if they defile or waste the water, they will wait to ambush and attack them unawares. Even if the travelers to their oasis are respectful of the oasis, they might try to capture one of them to feed on later.

While the Karoo can attack with claws, they prefer to use their long serpentine-like tail to constrict their prey, crushing them to death. Once their prey is grappled, they often will burrow into the sand to suffocate the creature while they constrict them.

The Karoo also have a burrow-like ability that allows them to swim through sand as if it were water. While under the sand, they have a type of vibration sense that will enable them to detect prey on the surface, where they leave their tails just below the surface, ready to strike and grapple. They do have to emerge from the sand periodically to breathe but can stay submerged below the sand for up to thirty minutes at a time.
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The Karoo is found alone or in small family groups. If locals know of a Karoo living at a particular oasis, they will leave out offerings when they visit the oasis to appease them during their stay. The Karoo speak their own language and have a 50% chance of speaking another local language. They learn these languages from listening to travelers they spy upon while they rest at the oasis. Because of this, some Karoo knows much of the local lore and news.