The first time Lan Huan sees him, he thinks it’s a trick of the light. The sea glimmers like translucent pearls off of the man’s pectorals, polishes his long wavy hair like jet. But the most fascinating part of him must be the thousands of tiny glittering scales lining his lower abdomen, down, down, down to a pair of translucent olive fins that shimmer like gold in the summer light. Lan Huan breathes in, but the salt spray somehow tangles in his lungs. (Mermaid AU)

Pale skin, a beautiful face, and dark hair with a Lan headband were all unsurprising, but his ears were capped with blue frills the color of the wall hangings in the Teaching Hall, and below his navel he had a tail, blue and white and tapering to the size of Wei Wuxian’s waist where it dipped below the water. The cold and the shock were finally too much - Wei Wuxian fainted.

Nie Huaisang rather liked their Neighbors. He was aware that that was widely viewed as being a little bit odd of him, but it wasn’t any more odd than his general distaste for training his saber – though combined with his passion for pretty things, fans and clothing and paintings and birds, more than one person had not-so-subtly implied that they thought Nie Huaisang might be a changeling. (They only ever implied it once – Nie Mingjue seemed to have an extra sense for finding out when people were being cruel to his brother, and no hesitation whatsoever about beating the living daylights out of them when he did.)

A very specific part of Jin Ling's Yunmeng Jiang heritage makes itself known when he comes of age. His friends help him out.

There's a mermaid bleeding in the lifeboat. Wei Ying stands over the mermaid on the ship deck with his thumbs hooked into his own belt, coat swung back behind him. The mermaid looks at him like he’s a particularly pathetic bug, even though Wei Ying isn’t the one laying flat-out on the deck looking like a- well. A fish out of water, basically. Wei Ying crouches in front of him and the mermaid bares his teeth, presumably to warn him off of touching or coming closer. Wei Ying holds his hands up, but frowns severely to establish dominance. “Hey, buddy,” He says. “It’s not my fault you decided to bleed all over a lifeboat. We need those.”

Prompt: Along with forming a golden core most cultivators gain the ability to shapeshift. What they shift into depends on the cultivator, but there are certain tendencies in bloodlines. Jiang Cheng has shifted exactly once in absolute privacy. He didn't stay shifted after finding scales and claws instead of feathers and wings, some sort of reptile from the Yu bloodline. He's since been pretending not to be able to shift at all, but you can only deny your nature for so long.