Reverse Cursed Technique

Reverse Cursed Technique (反転術式) is a special type of cursed technique that takes cursed energy and reverses it into positive energy. It is a very complex technique and is mainly used to heal human bodies.

Description
A reverse cursed technique processes negative energy into positive energy by taking two sources of cursed energy and multiplying them by one other. As a result, the energy that destroys becomes energy that creates, and negative energy becomes positive. Despite sounding simple enough, producing reverse cursed energy is extremely complex and difficult to perform for most jujutsu users.

Reverse cursed energy can be used for various purposes, but most commonly healing. Cursed energy comes from negative emotions, which are unfit for healing living things. However, cursed spirits that are made up of cursed energy don't require a reverse cursed technique to heal. Jujutsu sorcerers use reverse cursed energy mainly for generating new flesh to heal human bodies. While very few sorcerers can utilize a reverse cursed technique, there are even fewer that use it to heal people other than themselves.

Cursed Technique Reversal
Reversed cursed energy can also be used instead of regular negative energy to power a Cursed Technique Reversal. By applying positive energy, the effects of the technique will be reversed. For example, by fueling the Limitless technique with positive energy, Satoru Gojo can bring infinity, which is normally an invisible phenomenon, into reality as a tangible explosive force.

Mechanics
The cursed energy multiplication table below represents how a reverse cursed technique creates positive energy from negative energy:

Negative x Negative = Positive Cursed Energy (-) x Cursed Energy (-) = Positive Energy (+)

Shoko Ieiri
Shoko Ieiri is one of few people who can use a reverse cursed technique to heal others. She is considered incredibly valuable to Jujutsu High. Thanks to her talent for utilizing a reverse cursed technique and her medical knowledge, she earned her position as the school doctor. Despite being incredibly well versed in utilizing reversed cursed energy, she has never been good at explaining how it works to others.

Ryomen Sukuna
Unlike most cursed spirits Sukuna is capable of using a reverse cursed technique. He's incarnated in Yuji's human body, so he uses reversed cursed energy to restore it rather than cursed energy like a traditional curse would.

In order to push him to making a Binding Vow, he removed Yuji's heart and used his ability to heal as leverage. After they agreed on terms of Vow, he healed Yuji's heart and returned him from death. Mahito mentioned that a reversed cursed technique could revert the shape of a soul back to normal to remove the effects of Idle Transfiguration.

In Shibuya, when Sukuna found Megumi in a state of suspended death, he used a reversed cursed technique to heal him and ensure Megumi survived.

Satoru Gojo
In spite of being the most talented sorcerer in the world with the Six Eyes, Satoru as a first and second year jujutsu high student was always unable to grasp the complex nature of reverse cursed energy. He was completely unable to unleash the Cursed Technique Reversal: Red, failing to activate it in a fight during the Star Plasma Vessel Escort mission as a student.

After being nearly killed by Toji Fushiguro, Satoru tapped into the core of cursed energy and awakened the true powers of the Limitless. This allowed him to utilize a reverse cursed technique for the first time, restoring himself from a near-death state. Applying this same concept to his Limitless technique, Satoru was able to unleash Red on Toji in their rematch.

As a third year student, Satoru further mastered the Limitless and learned to use a reversed cursed technique constantly running through his body in order to preserve his brain while his technique is active.

Yuta Okkotsu
Yuta Okkotsu learned to utilize a reverse cursed technique early into his tenure as a jujutsu sorcerer due to Rika's immense levels of cursed energy and her ability to unconditionally copy techniques. Yuta first utilized it to heal Maki, Toge, and Panda all at the same time after they were injured by Suguru Geto. Suguru was extremely impressed that Yuta was able to use a reversed cursed technique.

Even after releasing Rika from her curse, Yuta retained the ability to use a reverse cursed technique. Since training overseas, Yuta has become even more proficient in using reverse cursed energy. While stabbing Yuji and technically killing him, Yuta immediately healed him to preserve his life. Shortly after Yuta used a reverse cursed technique to heal Naoya.

Uraume
Uraume is capable of using a reverse cursed technique to heal themselves. After being shot through the hand by Choso's Piercing Blood, Uraume used a reverse cursed technique to instantly repair the hole in their hand. Kusakabe immediately noticed this and assumed Uraume was on another level based on their ability to use an innate technique and a reverse cursed technique. Despite healing however, Uraume was unable to remove the poisonous effects of Choso's blood from their body.

Trivia

 * The Sword of Extermination is imbued with "positive energy" similar to reverse cursed energy.