Kaishi

Kaishi' (宇宙) is the most potent dōjutsu technique in Kyo Hyūga's arsenal. It manifests as one distinct ability, that can be channeled through the of both of his Tenseigan eyes —  giving him the ability to manipulate the boundary between fantasy and reality.

Usage
Through the activation of his Tenseigan and his understanding of the Creation of All Things Technique, Kyo created a technique that grants him the ability to turn fantasy into reality. An example of this being that if Kyo activates the technique and imagines that the hair on someone's knuckles are on fire, this will become true. By imagining that flow of chakra in his opponents body has seized to exist ," he can prevent his opponent from using chakra at all. On the supplementary side, he can instantly heal any wounds inflicted onto him by imagining that it has already healed.

Weaknesses
Though Kyo's technique could possibly be considered one of the strongest techniques to exist, it has a vast amount of weaknesses. It's first major weakness is knowing that Kyo can only manipulate the boundary between fantasy and reality of one thing at a time. Its second weakness is knowing that Kyo needs to maintain a constant concentration on the object he decides to manipulate. Disrupting his concentration would result in ending the distorting in reality.