Who is Leif from Everlost and what is their importance?

Leif is the young boy who lives in the forest where Nick and Allie die in a car wreck. He wants Allie and Nick to remain with him in the forest, but he follows them when they leave. Starved for attention and companionship, Leif waits nine months for Allie and Nick to awaken after the accident. Just as he's about to cross over, Leif remembers that his name is really Travis.