Sakona and Ukona's Kekkei Genkai is a unique ability of the brothers that allows them to split their own bodies at the molecular level. Most often they use it to merge cells and exist in one body, but the same trait also gives them the ability to enter the bodies of other people and destroy their cells from within. When Sakon needs help, Ukon can extend extra arms or legs from his body, strengthening strikes and blocks.
If necessary, Ukon is able to separate from Sakon so that the brothers fight on their own. Together they can attack a single target, but Ukon is weaker when outside his brother's body, and it is unusual for him to act as the main one. If they have merged with an opponent's body, they become vulnerable to any wounds the host receives, so the body's owner can kill them by taking his own life. If one of the brothers is wounded, they can merge again to heal; their recovery rate is much higher than that of an ordinary person, but it requires a large amount of chakra. If Sakon goes into a state of rest inside Ukon for treatment, it becomes much harder for him, because he is not used to being the main body, since he is weaker than Sakon, including in terms of endurance.
Kabuto Yakushi, having implanted the brothers' DNA, also gained access to this Kekkei Genkai.
