Netherrealm is where the Seven Kingdoms thrive.
There are seven kingdoms that correspond with one of the seven sins and a race. Each of the kingdoms has a king or queen that rules over it as well as a council made up of three people. This council is the king/queen's chosen successors. The current ruler can choose their own children or siblings to rule one of the chairs of the council. It is also possible for high-ranking government officials or generals to hold a space on the council.
Going over their history, succubi, incubi, and demons were one race. They were only called the demons at that point. When humans began to die at a fast rate, a group of demons decided attempted to create a being that could feed off of another source. Their experiments succeeded. This being fed off of lust. They found how to replicate this onto other demons. This was the start of the incubi and succubi. Now the demons are a separate race from those who feed off of lust.
Fenrir was created when werewolves needed shelter from hunters. Though they were stronger beings, they were little in numbers. Out of desperation, they reached out to the demons that roamed Earth. They were allowed to live in Netherrealm.
Fairies that were counted as impure were cast out of normal fairy communities. They had to roam Earth on their own or in tribes. They gained access to the Divine Gate and soon grew in numbers when they reached Netherrealm.
The angels that are cast out of Heaven are immediately sent to Earth. They could be recognized by their dark wings. Beings from the Netherrealm, who might be roaming Earth, are allowed to bring them to Mastema, a growing community of fallen angels.
Dragons, tired of being hunted and hated, were in desperation. They were accepted to live in Netherrealm.
Xanadu is the Kingdom of Demons. The kingdom is ruled by the Île Royal Family; the current Île Royal Family is made up of Faulkner Atlas Hyperion Île, Clarisse Marie, Sandra Williams, Eadric Helios, Ealgia Selene, Soleil Ambre, Millicent, Lionel Bluefire, and Canary Île. It is currently ruled by King Eadric Helios Île. During and before the events of The Guardians, the rulers of Xanadu were King Faulkner Atlas Hyperion Île and Queen Sandra Williams.
Fenrir is the Kingdom of Werewolves. It is currently ruled by King Gunnolf Wargyn and his wife, Queen Lykaios "Kara" Persef Wargyn.
Oradea is the Kingdom of Vampires. The kingdom is ruled by the Satoshi Royal Family; the current Satoshi Royal Family is made up of Reto Satoshi, Masato, Alvah, and Cian. It is currently ruled by King Masato Satoshi. The rulers before him were King Reto Satoshi and Beatrice Satoshi.
Finvarra is the Kingdom of Dark Fairies. It is currently ruled by King Russell Briarshine.
Melissani is the Kingdom of Dragons. It is currently ruled by King Bisterne Y Ddraig Goch.
Castitas is the Kingdom of Incubi and Succubi. It is currently ruled by the Royal Rose Family, Queen Evangeline Lussuria Rose being the present queen.
Mastema is the Kingdom of Fallen Angels. It is currently ruled by King Vassago Quemel Skrzydła.