A Combination Transformation where the user and their ninken become a single entity. It is a speciality of the Inuzuka clan, they fuse into a two-headed wolf, thus drastically increasing their size, and power. In their direct attacks, they demonstrate great efficiency. Furthermore, using techniques in addition to this gives birth to an extraordinary destructive power.
In the manga and anime, Kiba calls this technique by its full name, Inuzuka-Style: Human Beast Combination Transformation: Double-Headed Wolf (犬塚流・人獣混合変化・双頭狼, Inuzuka-Ryū: Jinjū Konbi Henge: Sōtōrō). However, the databook entry for this technique excludes the "Inuzuka-Style" section.
This technique is based on the Greek myth of Orthrus, a two-headed dog and brother of Cerberus.