The Gate to the Northern Heavens, also known as the Door of the Northern Depths, could be considered as a terrifying place that would cause the faces of the people in the Northern Heavens Spiritual Academy to change when mentioned. One year, there were outstanding students who had entered it. However, in the end, due to being unable to handle the pressure within that place, they suffered mental damage, resulting in them turning crazy, leading to the Northern Heavens Spiritual Academy to shut it down. After that, it was rarely ever opened again.