The Longest Journey (Dean Winchester Fanfic)
A lot like the brothers, Sam and Dean, Kaya and Kate travel together, saving people and hunting things, carrying on the family business.
After the girls' Mother's disappearance, they traveled a lot with their Dad, learning how to fight and hunt along the way. After the girls were old enough, their Dad left them with Bobby to search for their Mother alone. Kate understood but Kaya was angry with him for up and leaving them which caused a lot of problems between the two girls so Kate and Kaya split ways... until now.