Who is Major Donthorne from The Woman in White and what is their importance?

Major Donthorne is the owner of Varneck Hall, Southhampton. He hires a maid who has an affair with Philip Fairlie, who is visiting Varneck Hall. The maid, pregnant with Philip Fairlie's daughter, marries a church clerk named Catherick. Philip then marries another woman and has a daughter named Laura. The two daughters look alike.