The Whiptail Demon species is incredibly uncommon in the mortal realm, but in the Shadow Realm, they are almost the most common demon there.
They have very long, whip-like tails, as their name suggests, and they can change depending on their lifestyle. If they eat a lot of fish, they grow cat-like ears, in order to hear prey move.
If they fight with a lot of other demons, or humans, then they grow horns that store their power. The last would be the wings, which come to those who choose flight over fight.
Whiptail Demons have a certain blood-lust for humans, often burning them to death with their pyromaniac tendencies, or simply bringing them to their underground homes to torture them.
Despite this behaviour, they can come to trust particular humans, and even befriend them. They are extremely protective of their companions, whether they are human or not.