Supernatural could never end. Sure, the show ceases to exist without Jensen Ackles and Jared Padalecki, but as long as they’re still alive and kickin’ it, the show goes on. Hell, the two stars could be 85 years old, sauntering around with nurses, and you could still find a way to make it work. That’s the power of this series, and also a testament to its seemingly infinite sandbox — the best in the business, come to think of it. None of this is hyperbole. For 15 years, the long-running CW series has run the gamut and back when it comes to world-building. We’ve seen Sam and Dean Winchester ascend to heaven, discover other worlds than these, join the Scooby gang, play themselves, attend Supernatural fan conventions, and flip through channels. At some point, the depths of hell become so common...