Creepy-Meatball
The Slender Mansion was never empty. There were always people there, so it was kinda hard to get the house to yourself. Especially when you're a tiny midget who no one leaves alone.
Ben wasn't really an introvert, he just didn't like to be around people unless he was in a videogame, killing or trolling people.
Jeff on the other hand, loved to annoy and be an inconsiderate asshole to people unless he wanted what he called, "me time."