Who is dickon in the book called The Secret Garden?

Dickon helps Mary to bring the garden back to life. He assures her that though the garden has been neglected, it is still "wick," full of life. Dickon spends most of his time out on the moor, making friends with animals and conversing with them. He has a vast amount of knowledge about nature, which intrigues Mary and causes them to form a quick friendship. He lives in a cottage on the grounds of Misselthwaite with his mother, Mrs. Sowerby, and his sister Martha, along with their many other young siblings.