Blood is a corrupted element of magic, which almost always requires a sacrifice of the user's or their victim's blood. This can be put into rituals, hexes and vampirism.

Long ago humans started experimenting with their own blood. The results were horiffic, as dark creatures were summoned into the world, victims were robbed of their blood and life force to lengthen the life of the user. People casted terrible curses on each other.

Corrupted, Conversion

Blood can made to take any shape. It is also used to draw ritualistic signs and entire summoning circles.

With Blood magic one can summon terrible creatures from the underworld, cast curses on targets or drain them from their blood to use it to lengthen the user's life.

Someone who is drained fro mtheir blood will turn pale and thin, seemingly dried out.

It can be transfered from the user to a target, to restore health. This is a sacrifice from the user.

Blood can be read by skilled users. They can spot impurities and traces of disease in the target's body.

Drainage, one can completely drain a target of their blood. Summoning, where one can call on horrible creatures from other worlds, through a blood ritual. Curses, where the user inflicts a hex or curse upon their target by giving up a portion of their own blood.

The user will need blood for this form of magic, either from oneself or those around them.

The scale depends on how much blood the user has at their disposal.

Evil

Blood is primarily an evil and corrupted form of magic, but can be used for good purposes. One can make a sacrifice to heal others or spot diseases in a target's blood.

Blood users are often seen as savages and are mistrusted, as the vast majority of them works in cults where dark rituals are often practised.

Blood, either one's own blood or that of anyone else.

Blood represents both greed and sacrifice, which makes for a remarkable contrast of give and take.