Transformation Technique is a ninjutsu by which Pain would imbue a living human sacrifice with a portion of another shinobi's chakra. Under the influence of this chakra, the victim's body would transform, becoming an exact copy of the chosen ninja. The duplicate would inherit not only the appearance but also all the abilities of the original, including their kekkei genkai, such as the Sharingan, and unique weapons like Samehada. The original remotely controlled every movement of the copy, so it possessed the same knowledge and mannerisms, making the substitution nearly indistinguishable. The only limitation was the double's strength: its power directly depended on the allocated amount of chakra, which meant the most costly techniques were beyond its ability. As soon as the transferred chakra ran out, the victim would revert to their true form and immediately die.
Pain used this technique to create a barrier in the path of the Konoha teams, turning Yura into a double of Itachi Uchiha and Mukade into a copy of Kisame Hoshigaki, allocating thirty percent of the originals' chakra power to each. Despite the perfect resemblance, Kakashi Hatake vaguely sensed some falseness in the behavior of Itachi's double, although he could not immediately understand its cause.
