Complex sentence: In reality however, the form of Volrath was taken on by his shapeshifter, while the actual Volrath had himself shapeshifted into the form of Taraka, and all the while Sisay was under Volrath's mind control.
Split into simpler sentences: In reality however, the form of Volrath was taken on by his shapeshifter, while Volrath had shapeshifted into the form of Taraka. All the while Sisay was under Volrath's mind control.