The Many Walls of Limbo

 A prison without walls would hardly a prison be, and what the Fae lack in maintainance they more than made up for in construction. Encircling the great forest are four great barriers which, together, make escape unthinkable.

The first barrier is that of water in the form of the vast river Stymie. Her harsh currents encircle Limbo in their ever-clockwise roil, and her depths are home to spiteful things who find it joyful to sink and snatch and drown.

The second barrier is that of fire, in the form of a vile winged creature whose heads are three, whose eyes are thousands, and whose skin is molten brass. The horrid thing makes its home in a moat of what might be lava or metal heated red and viscous, carved in a ring about two miles outside the Stymie.

The third barrier is that of stone, in the form of a great wall or basin in which Limbo rests. The height of it is about twenty-five miles, and it is smooth as still water save for the nests. All sort of harpies and birds of prey and other roosting things hunt any who have survived the first two barriers and use their husks to feed their young.

The fourth barrier is that of air, in the simplest form: for as far as the eye can see, from North, South, East, or West, there is Nothing, not even air to breathe.

What thorough jailers have we, the damned.