Black Blood

The Black Blood is a type of black blood cell created and developed by Medusa the Witch, the sister of Arachne. It was created with the purpose of making a new Kishin by injecting the experiment's subject with Black Blood. Crona and Soul Eater Evans have so far been the research specimens for this experiment.

PROPERTIES
The Black Blood, as its name suggests, takes on the shape of normal blood cells, only pitch black in colour. Since its primary function is to make whoever it infects into a Kishin, the Black Blood induces insanity in the person who is infected by it. The madness of the Black Blood has different effects, depending on the user. Maka enters a sort of crazed and demented euphoria, Crona becomes more violent and Soul, who rarely uses the Black Blood because of the consequences, is constantly persuaded to use the Black Blood's power by Little Ogre in the Black Room. The main purpose of the madness is to erase all fear in the users, which prevents hesitation or weakness of will during battle. It is possible for a person to have his/her blood completely replaced by Black Blood. Likewise, Demon Weapons can be melted into the Black Blood, which in turn, turns them into a Dark Weapon. The madness of the Black Blood can be potent, but with enough strength of will, it can be controlled. However, using too much of the Black Blood's power beyond one's capabilities risks the person being devoured by the Black Blood and the insanity it produces.

If a person manages to control the Black Blood, he/she has full control of the abilities the unique substance offers. One of the Black Blood's properties is that it can hyper-densify to the user's will. When a user is cut and the Black Blood bleeds out of the wound, the user can will the Black Blood to harden and take on the shape of sharp objects, such as blades or needles. This is used as a counter-attack. It can also take on the form of a protective armour for the body. However, without the user's will, the Black Blood does not harden, meaning that this property is not an automatic function of the Black Blood.

The Black Blood also grants the user almost complete invulnerability. The Black Blood can harden the entire body, making it impervious to slashing or crushing attacks. Crona and Maka both exhibit this characteristic of the Black Blood, shown when Maka is stabbed by Crona, but is not even slightly affected by the attack. If the user is wounded, the Black Blood can harden and staunch the wound, preventing it from bleeding and healing the wound incredibly quickly. A great amount of strength is needed to break through the user's Black Blood, but it is possible to do so.

The user's speed and strength is also enhanced by a great deal when using the Black Blood. Crona, who is frail and rather unathletic in appearance, can move incredibly swiftly and can stop strong physical attacks with one hand. This makes the user a formidable opponent in battle.

The Black Blood also has a speculated infectious property. Black Blood can very easily be infected from one person to another. Ragnarok, a Weapon made up of Black Blood, immediately infects Soul after injuring him with his Weapon form. The Black Blood can also infect people via Soul Resonance. However, because of the Black Blood's highly dark properties, individuals who have a Soul Wavelength that dispel darkness (like Maka's Anti-Demon Wavelength) can only be infected by the Black Blood temporarily. Creatures made up entirely out of Black Blood can also fuse with other Black Blood users.

The power of the Black Blood is immense, but if a large amount of a person's Soul Wavelength (like a Soul Menace attack) is applied to the user, then the user's bond with the Black Blood is temporarily broken, leaving the user unable to use Black Blood for some time. Therefore, Wavelength-based attacks are one of the best ways to fight against Black Blood users.