Blood

Blood (BL) is a magical reagent which figures in the ritual magic of several worlds and the manufacture of Bloodspawn on Serpent Isle, although it is most prominently used in the necromantic arts of Pagan.

Pagan
Pagan is one of the only known worlds on which blood is regularly employed as a common magical reagent. In the arts of Necromancy, human blood is required for the creation of spells of summoning or communication with the dead, as it is said to possess the essence of mortality. Blood for such ritual purposes could commonly be found in the Catacombs of Tenebrae, although it seems unclear as to how it arrived there.

Sosaria and Britannia
Blood has never been a common component in the spellcraft of Britannia, although some few specialized rituals call for its use. Both Mondain and Nicodemus wrote works concerning the use of blood sacrifice in certain ceremonies, and the mystic process developed by Astelleron to craft intelligent golems required blood gathered from Stone of Castambre. The assassins of the Fellowship also appear to assigned some ceremonial significance to blood, as they would methodically collect it from their victims during ritual slaughter, and writings by Britannian mages further indicate that the popular reagent blood moss was thought to only grow where blood had been shed, leading to rumors in later ages that some villainous spellworkers would go so far as to sacrifice virgins in the hopes of cultivating the plant.

Serpent Isle
On Serpent Isle, blood was necessary to create the highly dangerous reagent bloodspawn, which was used in a variety of dark and violent spells. By mixing human blood with the pulverized mineral Stoneheart, a magic user may craft this diabolic agent, which is said to eventually drive those who possess it to madness and depravity.

Due to bloodspawn's illicit nature and its potential to corrupt, the Council of Moonshade sought to curtail its manufacture by outlawing ritual blood letting devices, although this prohibition appears to have been largely disregarded by most mages of the city.

Earth
Blood-based magic and ritual sacrifice feature prominently in a number of Earth traditions, ranging from the Blóts of the Germanic pagans to the animal oblations of early Judaism. Blood is often seen as a symbolic stand-in for life energy in Terran beliefs, and is frequently used as a sympathetic link to its owner in magical practices. In many cultures, blood is also regarded as pollutant, and people or things contaminated by it may require ritual purification.