The practice of harnessing the magical potential latent in the blood of most people of Aios. To cast the magic, one needs to shed their blood, which they are then able to manipulate telekinetically. This manipulation goes so far as transmutation into equivalent amounts of other forms of matter or energy, however the amount of blood that is safe for an individual to shed in a single instance (let alone on a regular basis) only goes so far.
As such, the limitations of basic blood magic or often augmented with haemoglyphs. Similarly, because of its potency and power, blood does not spoil if stored quickly after leaving the body, enabling haematurgists to carry around a ready supply of additional blood in vials and other various containers.
The only people of Aios who are incapable of haematurgy are the sufferers of Ashblight and their descendents, often colloquially referred to as some derivative of 'pale' or 'bloodless'.
Because haematurgic blood is wielded telekinetically, it is possible for one to consciously redistributed one's blood throughout their body, such as diverting blood away from a fatally gaping wound threatening to blood out, increase sexual performance and arousal, and many more.
There are two forms of advanced magic available through 'raw' haematurgy that do not require the use of haemoglyphs - bloodbonding and healing. Bloodbonding ties something (either an item or a person) to the subject, while in the healing process shed blood functions as both a transmuted material to 'fill in' lost flesh and the doctor's toolkit that pulls it all back together.
Because the healing process is self-directed and does not strictly follow natural, autonomous processes, fleshcrafting is possible.
It is possible to pass on all of one's magical abilities and properties to another through the process of Inheritance, though the procedure is risky and painful.
The blood that one wishes to use for spellcasting must be from a self-inflicted wound. Blood pouring from a wound inflicted by another - whether one sought to be struck or not - is totally mundane. To avoid the discomfort of regularly self-harming, many on Aios opt for surgery or fleshcrafting to introduce consciously-controlled 'valves' on their body to let blood flow painlessly.