Chinas Ranking
Different countries use different terms and ranks to assign cursed spirits and Jujutsu sorcerers. For Example, Shikigami or curses are called spirits by the Chinese and other countries.
In China, Sorcerers that use Jujutsu are called Cultivators, and Cursed Techniques are known as Spiritual/Martial arts. The way they measure a cultivators strength are the following:
Earth, Heaven and Star rank. Each of these stags have 3 more sub stages called beginner, solid and peak.
The weakest humans are at the beginner Earth stage by default, while people at the level of Special grade and beyond are at the Peak of Heaven rank and beyond. No one in China has reached their idea of the strongest possible, which is represented with the Peak Of star rank.
Haoran's nimbus cloud is an extension of his innate technique which is just a partial summoning of a much bigger cloud.
Sun Wukong while incarnated in Haorans body only has access to less than 1% of his power. The gods are as old as humanity itself however, they were the first proper users of Cursed Energy. The Gods are a type of cursed spirit that are all older, but way stronger than ordinary curses. They have never been exorcised once and were instead sealed away. The stronger the emotions that are felt to that particular god, the stronger they become.
In Korea, they call Sorcerers, Awakend People, but they still use the regular Jujutsu Terminology such as Cursed Techniques or Shikigami. Their ranking System uses stars that go from 1 to 6. 1 star being just above a 'normal' human and 5 and above being the Special grade Status.
Hikaru is a descendant of a former Zenin clan member who was the younger brother of a Ten Shadows user. After getting into an argument with him the ancestor got kicked out of the clan never to be seen again. In an attempt to get revenge, he created a shikigami from a multitude of cursed spirits. This created a direct opposite of the ten shadows mahagora called Mahakala, the black demon. Its ability allows it to get stronger over a certain period of time indicated by the flashing of its eyes. At the start its only as strong as a decent special grade but after 3 days it is physically as strong as Mahoraga but still much weaker in comparison. The Ancestor never got to carry out its revenge and instead entrusted this duty to his descendants. The Shikigami is cursed in the fact that once the current owner dies it will be automatically transferred to the next available host. If there are no suitable hosts it will be allowed to roam free which would basically spell the end of the world.