John Brown is Queen Victoria's aide and is seen both explaining things on her behalf and working to cheer her up. He is shown to be extremely serious, even keeping a straight face when pretending to be Prince Albert through a hand puppet. He takes pride in explaining things, but does not assume control over Queen Victoria or override her speech in any way. He occasionally suffers physical abuse at her hands, such as when she had a horse step on his head to make him be quiet, but he takes this all in quietly and never complains.
In the anime, John's role is replaced by Ash. John Brown is based off of the real servant to Queen Victoria, who was a favorite of hers.