Okay so this is some 'lore' on my oc Shadow's dragon and a little bit why she even has it.

The pure black Norse dragon with the name Dušnimojster, meaning soulkeeper as it was a reaper of sorts. It's appearance is pure black where it kinda looks like a void besides the two bright orange eyes it has, its body is serpent like with no appendage besides a pair of wings and spikes along its head and down its tail and two on the sides of its head and one on its snout. Depending on what kind of soul someone is Dušnimojster will either leave them be, help direct them to where their supposed to go or seal them away into its own form. The reason this creature had even bonded with Shadow is because of a ritual her village does when one comes to age, now a creature bonding to a person that does it doesn't always happen. It's actually a bit rare for that to happen but everyone in the village she grew up in went through it so it wasn't anything out of the norm, but when they did hers the dragon had appeared there and it's rune appeared on her, bonding it to her. Which the rune is the dragon tattoo that's on her back. Though besides that time the dragon hasn't appeared in its full form in our realm as it can't unless Shadow calls it to, even then usually it won't be its full size. It'll more so appear in the same dragon form but just the size of a household cat. But it can show it's power of passing souls but it has to be through Shadow more times then not. So when shes awake and brings the power out herself her pupils dilate into clits and her red eyes change into the bright orange color, the white of her eyes also go black, though it usually only last a few moments before she returns to normal. Though there are many who die daily the dragon can go and sort with their souls when she's asleep, it'll just be on a different plain of existence.