Raven

"The way she explained it, it's like a door," Karla said, settling in. "Or more like a series of roads, perhaps? Never mind, the precise analogy doesn't matter. Since you're linked to the Netherverse and the Netherverse is a great cosmic crossroads, you can get to anywhere--and, sometimes, things can get to you. Like your brothers, you know? She's not sure if it's because they're linked to you by blood, or by Trigon's powers, or if they have rudimentary access to the Netherverse, too, but if you walk through a door to get to them, they've figured out how to open it from the other side to get to you. Follow me so far?"