Blood

Blood is a liquified substance in some organisms, like humans, that carries oxygen throughout the body. According to the Book of Shadows, warlocks do not bleed when wounded, implying they do not have blood in their bodies. The substance is drunk by vampires, who require it in order to survive, and it is also used in several spells and potions, either for blessing or as an actual ingredient. The warlock Nicholas possessed the power to boil blood and kill his victims from the inside. When blood is transmuted by an alchemist, the transmuted individual will become temporarily immune to witches' powers.

In Witches
In witches, their powers appear to be in their blood, which explains how powers are passed down, so, should a mortal infuse their blood with the blood of a witch, they gain their powers.

In Demons
Upper-Level Demons have red blood, while Lower-Level Demons like Scavengers bleed green. When a demons blood is transmuted by an alchemist, they temporarily become immune to the powers of witches.

In Warlocks
Warlocks, or, at least, some warlocks do not bleed when wounded or their body is pierced, implying they have no need for blood.

In Gypsies

 * For its individual article, go to gypsy blood.

The blood of a gypsy is used as an ingredient in several potions, including the vanquishing potion used by Pilar, Phoenix and Patra on the Slave King and the To Separate a Witch from Her Powers potion.

In Vampires
Vampires require blood to survive, and use their long, sharp fangs to draw it from the veins and arteries of human beings. Should vampires drink blood while in bat form, it converts the victim to become one of their own.

Spells and Potions

 * To Call a Lost Witch: Blood is the final ingredient in this ritual, and is spilled into a cauldron with rosemary and yarrow root before the witch chants the last two lines; blood to blood, I summon thee, blood to blood, return to me.
 * Spider Demon vanquishing potion: The Charmed Ones used their blood to bless the vanquishing potion they mixed to kill the Spider Demon.
 * Slave King vanquishing potion: In the potion used by Pilar, Phoenix and Patra to vanquish the Slave King, gypsy blood was mixed with henbane and mandrake root as an ingredient.

Scrying
Blood can also be used by witches and warlocks in the art of scrying. The blood of the demon or person sought is applied to the scrying crystal, which is then swung over a map.