Katie Sinclair's Links
Katie and Matthew are friends. Katie thinks that Matthew is a nice kid, and they get along well. She's grateful for his help and wants to help him in return. Beyond that, it is difficult to say. They have very different personalities and have little in common. They are a solid team when there is work to be done, but outside of that, they have their own things to do.
Matthew sees Katie as a friend. She came to him for aid, and he will do everything he can to help get her coven back. He appreciates her company and values her friendship, even though he doesn't really understand the whole witch thing. Before he met Katie he didn't really believe in the supernatural (he doesn't really count himself as supernatural or mystical; he just thinks that being a ghost is a normal part of death and the afterlife, and even demons fit into his worldview to some extent).
In return for Lucy's help in finding her coven, Katie agreed to teach Lucy magic. Katie takes her responsibility as Lucy's teacher seriously. Katie also grew very close to her energetic student, who is so completely different from her, yet shares the same interests in magic. It's all so different for Katie, who until now has been too busy for much social interaction, let alone a love life, but she really cares for Lucy.