Who is Laurance Royston from A Test of Wills and what is their importance?

Laurance Royston is Charles Harris's land steward. He has taken care of Mallows for Colonel Harris since he was in his twenties, almost twenty years. During the course of the book, it comes out that Royston was involved in a terrible automobile accident when he was young. He killed a child and was injured himself. He borrowed money from Colonel Harris to settle the accident, but it has haunted him in nightmares at times.