The dark realm

Introduction
The Dark realm is an evil dimension, home to the mysterious being Sixteen and many other strange and uncomprehesible horrors.

Appearance
In S1 Ep 11, Phil enters the Dark realm to his own dismay. After the event, he explains what he saw.

He said it to have the hanging and impaled bodies of several sixteen-year olds, who's fates, until then, were unknown. Details beyond this are untold, and never will be, as the only living things that know are Sixteen, and Phil, who doesn't talk about it, as it heightens the occurance of The Other.

Trivia

 * Anyone within proximity of Sixteen can be forced to enter the realm, seen with Phil and lyle
 * The location of the Dark realm is unknown, but is said to not be within our own dimension
 * a common theroy is that Sixteen was born in this world, but is usually disregarded as fake