Demonic cultivation (鬼道) is a path of cultivation (supposedly) founded by Wei Wuxian.
Unlike regular cultivational practices which use spiritual energy (灵气) stored in the dantian, demonic cultivation manipulates resentful energy (怨气) given off by walking corpses. Notably, demonic cultivation can be accessed without a golden core.
Conversation in the Orchid Room
The basis of thought within demonic cultivation can be traced in Lan Qiren's scenario:
"There is an executioner with parents, a wife, and children, but before he died, he executed more than one hundred people. He suddenly died in the public and, to punish him for his deeds, he was left on the streets for seven days. With the repressed energy of resentment, he started to haunt and kill. What should be done?"Lan Wangji, as representative of orthodox cultivation, replied:
"First, liberate; second, suppress; third, eliminate. The initial approach is to utilise the gratitude of his relatives and grant his dying wish, set free what he could not let go of. If it fails, suppress it. If the crimes were extremely wrongful, and its energy of resentment does not dissipate, exterminate it completely. The cultivation world should precisely keep to this order of measures. No errors should be allowed."Wei Wuxian, however, postulated a different solution:
"Because the executioner died in such a way, it is only natural that he turned into a ferocious corpse. Since he executed more than one hundred people before he died, why not dig up the graves of these people, arouse their energy of resentment, collect the heads of those hundred people, and use them to fight with the ferocious corpse…There are some things that have no use after liberation, so why not find a way to make use of them? When Yu the Great tamed the flood, obstruction was the inferior method, and redirection was the superior. Suppression is the same as obstruction, so isn’t it inferior…Spiritual energy is energy; resentful energy is energy as well. Spiritual energy is stored in the dantian. It can split mountains and fill oceans, available for human use. If so, then why can’t resentful energy also be used by humans?"
Following his escape from the Burial Mounds, and now without a golden core, Wei Wuxian found himself turning to the methods of controlling ghosts and zombies which he had discovered to escape from the prison which would have trapped him. His control over resentful energy allowed him to control corpses via flute music, and the battlefield against the Wen clan was where the Yiling Patriarch thus made his name. Following the invention of the Stygian Tiger Seal, it became apparent that, at its basis, demonic cultivation was a fast and easy way to gain power.
In the next 13 years the next person to rival Wei Wuxian in talent at this was Xue Yang - between repairing the Stygian Tiger Seal, Xue Yang also developed a way to induce Corpse Poisoning, a cure for same, and a way to make living corpses.
Making Fierce Corpses
Summoning of Painted Eyes
As if they saw or heard something hilarious, the pair of paper mannequins giggled incessantly. At the same time, the eyes painted with human blood spun rapidly inside their sockets. The sight was truly stunning, but also truly frightening. Standing before them, Wei WuXian lowered his head in salutation.
Involves channelling a spirit to see his/her past memories. Memories are shared exactly as experienced with an emphasis on emotional state/feeling.
Empathizers require a Supervisor to preside over the ritual and pull them out of the trance if things go south. A straight forward means of spirit communication with high risk of insanity and complete bodily possession.