NCT x OC, supernatural:

Mia was a hardworking 17 year old girl. Grew up with her single dad as a only child, great GPA, plans on moving to Australia where her Aunt lives and attending to college there. Then, she starts having these nightmares. Within a couple nights of the recurring scares, she wakes up with this tattoo on her stomach. She figures it's a prank, but it won't come off. Goes to school, asks friends, no one is fessing up. The tattoo honestly doesn't look that bad (she had another one she wanted for her birthday, and more than likely it's from her friends, but she rolls with it)

The "tattoo": https://www.google.com/url?sa=i&source=images&cd=&ved=2ahUKEwif1bvTqenfAhUFwVkKHdr4AYwQjRx6BAgBEAU&url=http%3A%2F%2Fwww.tattoochief.com%2Ftattoos%2Ffor-women%2Fmoon%2Fbicep%2Fpage-4&psig=AOvVaw20GkuYaig3xXNwSZFx49I5&ust=1547419669317435 

Turns out it's not a tattoo, it's a "mark"-a mark that makes her a "core" or "balancer" of energy and abilities within the supernatural community.  She was a planned occurrence that could take away the power of any supernatural, harvest supernatural energy, and or give energy away. Extremely valuable, extremely powerful, and rare. 

This is a small sum of the ideas I am having (currently working out the kinks) and would love any ideas/collaboration to make the story have a good plot!!! 
My biggest issue which I need advice for is "marked" people (as I have decided) are NOT based off of blood line or in coming of a specific time (I am willing to have a possible "birthday" thing, but I want something more or different preferably). My main thought was that finding a marked person is like predicting a eclipse in the B.C times, where they used old zodiac and religious calender's to make predictions, and maybe you could get pretty close, but to have it exactly right just based off of the systems available nearly ever happens.

Again, i would love to throw around/discuss ideas with anyone who wants to! :D 
TYSM! <3333