The arte of using blood to bargain with otherworldly beings. While similar in effect to Thaumaturgy, Hemoturgy almost always achieves the effect requested in the deal. However, the terms are prone to unintended side effects. And the caster must be sure their demand does not outpace their supply, for their patrons are greedy.
While it is not strictly a magic of curses and decay, these types of acts are the most typical. This is because the Patrons of Hemoturgists see these acts as partly beneficial to themselves. If the hemoturgist wishes to use their power to kill and the patron is a demon of war, then they would indirectly profit. If somehow the practitioner has a benevolent patron, then a similar reduction in price may occur for an act of creation.
However, make no mistake. No matter the patron, a blood price will be set. The otherworldly sources the power of the effect from the blood. The only question is how much of a tax they take for themselves.