Due to extensive experiments to his own body, Orochimaru was unable to use Sage Mode and thus had to create and alternative way to make use of senjutsu. Orochumaru thus used Jūgo, whose body naturally produces an enzyme that triggers bodily transformations, and created a brand of cursed seals that would feed off the wielder's chakra and give them Orochimaru's senjutsu chakra. Because of this, the cursed seals are compatible with members of Jūgo's clan allowing those, such as Jūgo himself, to transplant some of his flesh to Sasuke.
Orochimaru usually gave his cursed seal to his most powerful and unique followers and guinea pigs to either make them his strongest warriors or to prepare them to become a potential host bodies in the future or simply as test subjects. To apply a cursed seal, Orochimaru usually bites his intended target. As he had sharp fangs and an extendible neck, this was a relatively simple task. The seal then appeared on the body of the victim near the puncture wound, which would cause them to subsequently lose consciousness. The design of the seals could either vary from person-to-person or was dependent on the type of seal Orochimaru chose to brand the victim with. If the victim had survived the application of the seal, they would awaken with the first level of the seal activated and enraged due to the seal's influence.
The seals have two different levels, and the types of transformations differ from seal to seal. When inactive, the seal is simply a black tattoo on the user's body. Orochimaru has a wide array of cursed seals, so the appearance and power of the seal will usually vary. Each seal always has three identical marks arranged in a circular pattern. When first activated, the marks on the seal glow and replicate, spreading over the user's body. This is known as the first level of the seal. The degree to which this occurs is dependent on the user, and the degree to which it spreads is proportionate to the overall effect it has. Normally, the wearer of the seal will also experience slight pains during the activation of this level.
The second level of the seal causes the black marks to completely envelop a user. This is followed by many unnatural alterations of the user's body. Once transformed, common features shared include yellow eyes with a black pupil, skin changing colour, and longer hair. When in this level, the seal also eats away at the mind and personality of its users, driving them to madness if used for too long. It also takes quite a toll on their body, since they are being mutated by the seal. Aside from the first and second levels of the seal, skilled users of the seal are able to perform partial transformations in which the aforementioned mutation caused to the user's body in the level two state can be used without altering the entire body. The power of the cursed seal can even synchronize with the user's regular body with extended use, exponentially enhancing the abilities of their normal state.
The Cursed Seal of Heaven is one of the strongest of Orochimaru's cursed seals, the other being its counterpart, the Cursed Seal of Earth. The seal consists of three tomoe, similar to the Sharingan, which, when activated, spread flame-like markings across the user's body. Like all cursed seals, the user receives increased chakra levels and physical capabilities when the seal is active, to the point where with the second level, Sasuke was equal in power to Naruto's one-tailed form when he first used it. The seal was applied at the left side of the back of both Sasuke's and Anko's necks.
Anko received her cursed seal when she was a student of Orochimaru. She, along with nine others, were the first people to receive a cursed seal. She was the only one to survive the application, establishing the one-in-ten success rate for the procedure. Because she lacked the will to use it, her seal receded, and Orochimaru wiped her memory. Orochimaru was able to briefly reactivate the seal when they fought in the Forest of Death before the Third Hokage sealed it off again. It was fully removed when Sasuke used it as a medium to revive Orochimaru's consciousness and body via the Evil Releasing Method.
When stage one is activated, a flame like pattern is from over your skin, causing extreme pain. The flame pattern originates from your cursemark insignia, and spreads across half your body. Stage one can last forever.
- [25% reduction to Ninjutsu]
- [No handseals]
When the second stage is activate, the skin of the user is turned dark-grey and the hair grows and turns dark blue. The eyes also turned dark grey. Additionally, he grew webbed-claw-shaped wings from his back which he could use to fly and glide, and a dark, star-shaped mark appeared across the bridge of his nose. Stage two last five post before reverting to stage one. The stat boost persists.
-[No longer have to use handseals.]
-[50% reduction to ninjustu.]
-[Ninjutsu is boosted one rank]
-[Ability to fly]