Kemmler is considered to be one of the most powerful warlocks and necromancers of all time. He practiced what he called 'true magic' to control life and death. His main focus was necromancy, for which he was renowned. He was deemed such a risk that the entire White Council hunted him down in 1961.
He had power over the dead and demons, was allied with most of the Vampire courts, every "nasty" in Europe, and some of the more malicious Faeries. He had his own cadre of apprentices and thugs, called "Baby Kemmlers" by Harry Dresden, who followed him in his footsteps and practiced the darker arts.
Kemmler had learned a way to bind his will to shades as well as the dead, to devour them in order to feed his own power. This was what allowed him to defy the White Council for so long. This secret of using ancient spirits for the Darkhallow is written in The Word of Kemmler.
He was attempting the Darkhallow Ritual when he was defeated by the White Council.(ref?)
Kemmler has been killed by the White Council seven times over the course of a number of wars with him. The first being in 1890's, the second near the end of WW2 and most recently in 1961. It was during this last attempt that the entire White Council down to the last wizard was devoted to killing him.
He was responsible for World War I. There was about 150 years of history behind it and Kemmler had his hand in several facets of it. He vanished after WWI then reappeared in WWII when he animated mass graves and rampaged through Eastern Europe. It's uncertain how many he actually killed.
Justin DuMorne, a Warden at the time that the council destroyed Kemmler, pulled Bob out of the ruins of Kemmler's lab, recognizing the air spirit of intellect and wanting it for his own uses. Bob was later recovered by Harry Dresden after his final confrontation with DuMorne.
In the series Edit
- Main article: Ghost Story
- Main article: Cold Days
In Cold Days, Harry learns from Bob that Halloween night is the only time that the Darkhallow could turn a wizard into an Immortal since. This is because Halloween Night is the only time of the year when the "locked stasis of immortality becomes malleable"—they can add new power to their mantles of immortality by feeding: taking in new energy. He also learn that Halloween is the only time they are vulnerable to being killed.
The Heirs of Kemmler Edit
- Main article: Heirs of Kemmler
The Heirs of Kemmler intend to call up ancients spirits using the Erlking and then devour them for power on Halloween Night during the powerful Darkhallow spell that will turn one of them into a god-like being with ungodly powers.
- Main article: Darkhallow
The Darkhallow is a ritual whereby one elevates themselves to near godlike power using necromancy. Kemmler attempted the Darkhallow, as did Corpsetaker. However neither were successful.
The Darkhallow can only be attempted successfully on Halloween night.
Evil Bob: The Word of Kemmler contains: "Knowledge. Truth. Power. The master wrote down his teachings, wizard, so that those who came after him could learn from him. Could learn about the true power of Magic. What you call magic is nothing more than parlor ticks beside the power to master life and death itself." 
Kemmler's name could have come from a number of sources:
- The master necromancer of the same name from the Warhammer fantasy table top game.
- William Kemmler- who on August 6th, 1890, was the first man executed through the use of the electric chair.
- A corruption of Heinrich Himmler, the head of the Hitler's S.S.
In Cold Days, Harry learns that it is only on Halloween night the Darkhallow ritual can turn a wizard into an Immortal. Halloween night is when the locked status of immortality becomes malleable and an Immortal can add power to his mantle by feeding on energy, though immortals can also die on this night. Given that Kemmler was killed on Halloween (ref?) night in 1961, it is possible that he became an Immortal on Halloween long before he attempted the Darkhallow. This could explain why the White Council had to kill Kemmler seven times—the final attempt being on Halloween night in 1961.
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Dead Beat, ch. 3
- ↑ 2.0 2.1 2.2 Dead Beat, ch. 21
- ↑ Ghost Story, ch. 17
- ↑ Ghost Story, ch. 44
- ↑ Ghost Story, ch. 28
- ↑ 6.0 6.1 Cold Days, ch. 11