What kind of demon would Niall be? How did he become one? Whats his demon task (i mean he's pretty good at soul collecting as a human)?
LISTEN. This is not a demon? Or maybe it sort of is? But Niall is a kelpie. Niall transforms into a cute little pony and gallops around the countryside and tries to get people to hop on and take a ride, and when they do, he trots right into the sea and drowns them. He can also take the form of a very handsome man and lure folks that way. You’ll know him by the seaweed in his hair.
Alternately, Niall is a selkie, because I like thinking of Niall as a sweet baby seal.
Alternately, Niall is just a vampire who really likes to go out and meet people, ala vampire boyfriends, and did a lot of murders for many years before he met Zayn and managed to settle down and find some humanity. He still needs to go wandering every couple decades and get his ya-yas out, though, and Zayn needs a lot of alone time, so their relationship is sort of cyclical and has a particular rhythm to it. He might still do a murder occasionally, but they don’t really talk about that.