This technique allows Ukon to inhabit his brother, Sakon's, body, moving within it freely and emerging from Sakon at will. This allows Ukon to help Sakon in combat in ways that Sakon would not be able to do alone, such as emerging from Sakon's back to intercept surprise attacks or producing hands from Sakon's head to attack from angles that Sakon cannot. Alternatively, Ukon can add his fists to Sakon's punches and feet to Sakon's kicks, tripling their power. Until opponents become aware of Ukon's presence, they are likely to be confused by Sakon's inexplicable and unpredictable combat ability. Ukon can fully emerge from Sakon's body so that they can work together, but because of how much time he spends in Sakon's body he isn't used to independent movement and thus tires easily.
After acquiring Sakon's DNA, Kabuto Yakushi is able to use this technique through his Strange Transmission Distant Shadow; he refers to it as "Sakon: Twin Demons Technique" (左近・双魔の術, Sakon: Sōma no Jutsu). Kabuto creates mindless copies of select shinobi (the Sound Four, Kimimaro, Orochimaru) which he stores within his body using this technique. By producing the copies from his body, Kabuto can use the copies' jutsu.