Who is Nate Cross from Lock and Key and what is their importance?

Nate Cross is the boy who lives next door to Jamie and Cora, he meets Ruby when she's trying to sneak across the fence of the Hunter house to run away. Nate is the same age as Ruby and has many of the same problems though he puts on a public face that means most people don't realize his problems. Nate desperately wants to hide the fact that his father is abusing him with the idea that he can leave as soon as he graduates and simply never return