the world is randomly generated, and Herobrine cant do that. Herobrine makes 2x2 tunnels, randomly stares at you through glass or from a hill or something, and if you look at him directly for more than a couple seconds he kills you and takes any stuff that drops that he can pick up from where he was standing. and if you stare at him from in a building while he's looking through your glass, he'll break it. lol