Curse Seal

As a form of control, the Sound ninja Orochimaru will place cursed seals on those he wishes to grant more power. Orochimaru developed the enzyme to create the cursed seal from a young man named Juugo who sought help from him. Juugo's body naturally entered into this "Level 1" and "Level 2" state, which caused him to lose control and enter a state of powerful blood lust. Orochimaru experimented with this ability and developed a way to grant this power to other normal ninja. Once the seal is placed on a ninja the chance of surviving is one in ten.

Once in place the seal will grant the wearer the ability to access their real power. By releasing chakra, the seal becomes active and begins to forcibly pull out even more chakra. When the wearer releases the cursed seal to activate the extra chakra, they will lose their free will permanently over time, transforming the user into Orochimaru's slave.

When a user first receives the cursed seal on their body, they are only able to access the "Level 1" power. With time the infection can spread and gain a "Level 2" power. The Level 2 form will dramatically increase the wearer's power. When initiated, the Level 2 power will also manifest physical changes in the wearer. The seal will end up covering their entire body, the skin color will change and protrusions will begin to sprout from different parts of the body. The changes inherent in the different forms resemble the changes undergone by Juugo as well.

The spread of the Level 2 power can come in two fashions: 1) The natural spread of the infection over time. 2) The drinking of the Seishingan drug, which places the individual into a near death state. By ingesting the drug, the enzyme infection will forceful spread and cause the body to die. However, the use of the Four Sounds barrier jutsu will reduce the side effect of the curse and allow the body time to adjust to the level of infection without the individual expiring. Once the body is able to handle the infection, the users Level 2 power will then be fully activated.