AHHH I love designing tails for my tieflings!! I always try to give them unique tails...
Red has a prehensile tail.
Quinn has crystal spikes along it.
Sun had shapes.
Bal ends in two tips that are also prehensile and he can control 👀

My tiefling Nimeni/Nemo's tail is just a simple point really 🫣 though before I revamped her it was a tuft

It ranges from itty bitty skinny fish tail, to a thicker more classic tiefling tail, to this fun feathery/fluffy thing I like doing!