Forbidden Love

What if there were parallel universes out there? Specifically one that holds people that have magical abilities once born and never die of old age.
Mayella Rose lives on the planet Argothian and teleported to the human world, Earth, on her twenty-first birthday. Over the years of helping the humans, she saw nothing but destruction and hate, making her change her mind and decide to help the humans kill one another.
Being trapped for many years, an old friend, Skylar Aragon, comes to save Mayella from her supposed forever slumber. Finally free, she plans to get revenge on all living creatures on Earth.
On her and Sky's journey, they encounter a human male willing to help them travel the planet. His name was Shawn Hancock.
Shawn plans to turn Mayella back to helping the humans instead of ridding them all. In the process of changing her mind, little did Mayella know that the human Shawn was falling in love with her, and worse that she was falling for him.
There's only a couple problems for the immortal girl and human boy to fully falling in love: Argothian doesn't approve of human and immortal love, and Mayella's secret fiancé will get rid of anything in his path that keeps him from his lover.

~All the pictures I am using belong to their rightful owner. I am only borrowing them to give a description on what the scenery or people look like in my head. This is an original story that I have made up, along with character names. There is some adult language, blood, gore and stuff like that, so if you don't like then maybe this story isn't for you.~