Al's blood rune.
A Blood Rune, also known as a Blood Seal (血印, Ketsuin), is an alchemical technique used to bind someone's soul to an inanimate metal object. The iron in the blood will interact with the metal it is on, causing the object and the blood rune to form a symbiosis.
The Process[]
The practitioner must draw a rune in blood on an inanimate metal object (usually armour) which will bind with the iron in the blood. If the person whose soul is to be bound is through the Gate, the alchemist performing the transmutation must give a part of their body as a toll in order to pass through, retrieve the soul and bind it to the host object.
Overview[]
A person whose soul is bound to an inanimate object is able to freely control the object they are bound to. Within the series, the only instances of soul binding was done to humanoid objects such as suits of armor, but it was shown that any attachment (such as an arm or leg) to the armor could also be freely controlled by the soul within the armor. However, those who did not have limbs or appendages did not appear to be able to control much of their bodies, likely meaning a humanoid form is the only way for a soul bound to an inanimate object to function. A person whose soul is bound to an inanimate object feels no pain, hunger, temperature, or fatigue, thus enabling them to perform immense physical feats. Also, as the person has no body, they can sustain more damage than normal humans, placing the person in a state of high invulnerability.
Negative effects[]
The primary weakness of those bound to an inanimate object is the blood rune itself. If the rune is damaged in some way, whether that be interrupting the pattern, damaging the material it is written on, or altering the material of the rune, the person's soul is directly affected and can even fade from the object. The blood rune is literally a connection to the soul itself, so tampering with it can affect memories or even allow the user to be possessed. This makes the protection of the blood rune the most important task of the bound soul.
Although never mentioned in the 2003 anime (and as such, presumably not applicable to as it was ending when this fact was acknowledged in the manga) there is an even greater danger; if one's soul is bound to an inanimate object for too long, the soul and object will eventually start to repel each other. The person will start to experience moments of exhaustion, which cause that person's soul to disappear from the object, as stated by Al, who compares his body to a time bomb. This can lead to the complete destruction of the soul as it slips away to The Gate. This makes the blood rune only a temporarily effective technique, though this still took several years before any signs of problems began to show.
A final concern is the psychological effect of being bound an inanimate object. Barry the Chopper suggests that it is possible for the practitioner of the blood rune to be able to alter or even fabricate the personality of the person whose soul is being bound. While never proven, Alphonse Elric, a trained alchemist, seems to at least believe this is a possibility. Concerns such as these can lead to questions regardihng one's own existence and can be very dangerous to a person's mental psyche.
Examples[]
Gallery[]
