Why Herobrine?

Hello, I have recently noticed that there was a character that has been popping up a lot, and that was Herobrine, now I have heard his name a lot in the Minecraft community, especially in the short movie “HIM” and I notice that in your updates, you always say no Herobrine, which we have a funny joke if you weren’t always putting in that part of every update, now I have really known knowledge of this Herobrine in game of Minecraft but I always wonder why do you keep on doing that joke? If he’s not real and just supposed to be a joke? He’s not real right? And if he is then why are you holding him back why can’t you just bring him into the game I assure he’s probably not gonna be that much of a problem for you right? But again, I’m not a developer and you’re probably not going to notice this message anyways, so I guess all I’m just here to say is that, is he real or not?