The practice of attempting to communicate with the spirits of the dead in order to predict or influence the future.
The attempt to summon the spirits of the dead in order to gain knowledge of future events from them. The word necromancy derives from the Greek nerkrós, "dead", and manteía, "divination". Early necromancy is related to shamanism, which calls upon spirits such as the ghosts of ancestors. In the Middle Ages, necromancy came to be more associated with black magic and demon-summoning in general, sometimes losing its earlier, more specialised meaning.
Necromancy is the act of resurrecting the dead through the usage of magic.
Neil resurrects his best friend and secret unrequited love Angela Mason so they can still be together. She, however, goes mad and begins killing people from her old life, namely her cheating boyfriend and her best friend, whom he cheated with.
Walter Dixon, a screenwriter who wanted a Hollywood movie to be 100% accurate, wrote a screenplay that was basically a how-to book on necromancy. When the producers changed it and continued to pervert his original draft, he began raising the dead of Hollywood to kill those who wronged him.
The Egyptian god Osiris uses necromancy to resurrect he spirits of the two people a man named Warren murdered 30 years prior. In an attempt to keep Warren from being killed, Sam and Dean place him a salt circle, which steps he out of, allowing the ghosts of his victims to kill him.
When Dean is put on trial and found guilty by Osiris, his sentence is carried out by the ghost of Jo, whose death Dean felt responsible for. While Sam tries to stop Osiris, Dean waits in a salt circle when Jo appears in his motel room. Telling Dean not to blame himself, she turns on the gas oven and opens the window for a gust of wind to blow the salt away. As she is about to ignite Dean's lighter, Osiris is stopped by Sam, sending Jo away to the afterlife once more.
In World War II the Thule Society, led by Commandant Eckhart, carried out magical experiments on Jewish people in Vitsyebsk, Belarus, that eventually led him and his followers to reanimate the dead; he wrote the notes for these experiments in his red ledger. After being forced to flee and having left the red ledger behind because of the arrival of the Golem, both the Thule Society and the Judah Initiative began searching for the book. It was Rabbi Bass who found the book first, but he was killed by Torvald, a follower of the Thule. The book and the Golem were passed on to his grandson Aaron but they were eventually found out by Eckhart and captured. They escaped and killed Eckhart and his men, whose bodies they burned to make sure none of them would return. The book is then kept safe by Sam and Dean while Aaron vows that he will continue on the work of his grandfather and the Judah Initiative and look after the Golem.