The Moon Slaughter Devil Nest is a place located above the Southern Ocean that spews out terrifying amounts of yin energy. After Supreme Ocean Palace discovered this place and found out how terrifying it was they sealed the entrance and erected the Supreme Ocean Palace in order to guard it.
After the isolation barrier was erected over the entrance the Supreme Ocean Palace they left a gap that only opens once every five hundred years so that they could send disciples with bad aptitudes to see if the Moon Slaughter Devil Sovereign was dead because at that time they believed that it was that beast that was releasing the yin energy.
It is said to grow Netherworld Udumbara Flower within it. It is such a scary place that even cant stay within it for more than fifteen minutes or they will risk becoming crippled. It also holds a beast within it. While it is only at the Tyrant Profound Realm, but with the specialty of the Moon Slaughter Devil Nest that suppress Profound Strength even late-stage Monarchs will be suppressed down to the Emperor Profound Realm.
After all but one expert from Supreme Ocean Palace were killed, the surviving one sacrificed dozens of their strongest profound artifacts and a large amount of Purple Veined Divine Crystal to create an isolation barrier.
Because the barrier consumes so much energy, every three years a dozen Monarchs are needed to infuse Profound Strength in order to maintain it.
- The beast within calls itself the Moon Slaughter Devil Sovereign.