The Darkhallow is the most powerful necromantic rite known. The rite was first created by the necromancer Heinrich Kemmler, one of the most feared and infamous of all dark wizards. The rite is in essence a rite of ascension from mortality to godhood.
- Harry Dresden
- What happens if one of his heirs is able to do it?
- The heir would gain power such as has not been wielded by mortal hands in the memory of your race.
- Harry Dresden
- The Darkhallow. That’s what it is. A ritual, tomorrow night. Halloween. They all want to be the one to make themselves into a junior-league god.
- Power is ever sweet, is it not?
- Harry Dresden
- Can they do it without the Word?
- — Mab and Dresden on the Heirs of Kemmler completing the Darkhallow.If they could, why would they seek it so desperately?
It is necessary that the necromancer performing the rite summons as many spirits as possible in order to devour them for the spell gain a greater level of power—godlike power. 
A toned-down version of it is called Quickening.
The rite creates a vortex that draws in all life, among other energies, within about an area within a mile. The Necromancer forms all that energy into a big Circle, getting it moving around into a giant funnel and into the one who is trying to consume it—like trying to take in a tornado.
The Heirs of KemmlerEdit
Kemmler's Heirs 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.
In the seriesEdit
In Dead Beat, Harry learns from Mab that the Heirs of Kemmler are seeking the book Die Lied der Erlking to summon the Erlking in order to devour the powerful long-dead hunter spirits which accompany him on his Wild Hunt that Holloween night, thereby perfoming a Darkhallow spell the gain godlike powers.To prepare the way, the Heirs of Kemmler create fear and havoc and helplessness through the city by making a blackout. To get Shiela to recite the Erlking's book for him, Dresden explains why the Heirs want to call him up. He explains that they need to call up many ancient spirits to consume them to gain godlike power. She knows right away that he's talking about a "Rite of Ascension"—the Darkhallow. Dresden told Kumori he's going to stop them from doing the Darkhallow. Dresden asks Cowl how he is going to perform the Darkhallow without the Word; Cowl just laughs, walking away into a rift. It's now necessary for Dresden to find the Word himself because he has no idea what's supposed to happen during one and he has to stop it. So he and Butters set out to find it. Dresden explains to Butters about the Darkhallow and asks his help beating the drum for Sue, the T-Rex he plans to reanimate to stop the Heirs of Kemmler and the Darkhallow. When Dresden and Butters arrive at the scene, they see the vortex forming. With Anastasia Luccio, Donald Morgan and the rest of the Wardens wounded or killed, Dresden and Carlos Ramirez head into the vortex to get the bad guys and stop the Darkhallow.
In Cold Days, Bob informs Harry Dresden that Halloween night is the only time that the Darkhallow might turn a wizard into an immortal. This is because Halloween night is the only time of the year when the "locked stasis of immortality becomes malleable" and new power can be fed into the mantles of immortality. Halloween is also the only time they are vulnerable to being killed.
- ↑ 1.0 1.1 1.2 1.3 1.4 Dead Beat, ch. 21
- ↑ 2.0 2.1 Dead Beat, ch. 28
- ↑ 3.0 3.1 3.2 Dead Beat, ch. 38
- ↑ 4.0 4.1 4.2 Cold Days, ch. 11
- ↑ "Welcome to the Jungle"
- ↑ Dead Beat, ch. 23
- ↑ Dead Beat, ch. 29
- ↑ Dead Beat, ch. 34
- ↑ Dead Beat, ch. 35
- ↑ Dead Beat, ch. 39
- ↑ Dead Beat, ch. 41–42
- ↑ Ghost Story, ch. 46
- ↑ Changes, ch. 30