Demonic Revenge(Supernatural fanfic)

What if Sam and Dean had a sister? What if they never knew about her? What if the son of a demon they had killed wanted revenge?
What if that demon's son and their sister fell in love? They never knew of her because their father kept it a secret after getting together for one night with a lady he met a year after their mom's death because he was ashamed of it.

Kandice, 14, had a normal life with her single mom. She had tons of friends, was very athletic, and was loved by all her teachers. Her goodie-two-shoes reputation has kept her out of trouble for the longest time but will all that change when a cute demon on the path for revenge kidnaps her?

Brad Mitchell, 15, was a demon who's dad was killed by a certain pair of brothers. He had spent his entire life trying to avenge his father, so he didn't really have any friends and his mom had died giving birth to him. He planned to kidnap and torture their long lost sister until he met her.

Will it be love or hate at first sight?