Sōrei

Sōrei (双霊; lit. Paired Spirits) is a form of used by the Twin Dragons Yasaki Hatake and Katoku Hatake. It is unique in the sense that it began to grow stronger with each time the brothers cooperated with one another. Using Sōrei, they can communicate with each other on a mental level, as well as being spiritually connected to each other. This allows one to sense if the other is in danger, hurt, or in a state of extreme emotion. It allows their thinking to be synchronized, which leads to better cooperation on attacking. It also provides some resistance to genjutsu. One twin can awaken the abilities of another and so forth. The link between the two users are permanent, but it is one of the strongest spiritual connections ever witnessed.