A blood rune, also known as a blood seal, is an alchemic technique used to bind someone's soul to an inanimate object. The practitioner must draw a rune in blood on an inanimate object (usually armour) and call the wanted soul into it, filling the object with the soul. A person whose soul is bound to an inanimate object feels no pain, hunger or fatigue thus enabling them to perform immense physical feats. Also, as the person has no body, he or she can sustain more damage than normal humans, placing the person in a state of nigh invulnerability. He or she has only one weak point, the rune itself. If the rune is in some way damaged, the persons soul will start to fade from the object. This makes the protection of the blood rune the most important task of the bound soul. Sometimes, the person inside the object will start to question his or her own existence. This can be very dangerous to the person's mental health. Yet there is a bigger danger. If one's soul is bound to an inanimate object for long, the soul and object will start to repel each other. The person will start to experience moments of sleepiness, which cause the person's soul to disappear from the object. This can lead to complete destruction of the soul. This makes the blood rune only a momentarily effective technique.