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 integrating Sakon's cells into his body, Kabuto Yakushi is able to use this technique to generate mindless clones of other shinobi, including the Sound Five and Orochimaru, from his own body in order to perform their techniques.
- When Kabuto uses this technique, he refers to it as "Sakon: Twin Demons Technique" (左近・双魔の術, Sakon: Sōma no Jutsu).
- In the fourth databook, "Attack of the Twin Demons" and "Twin Demons Technique" are both mentioned by name in the Strange Transmission Distant Shadow entry, which may imply a difference between the two.