They had returned to their original physical bodies.
For most souls of other races, frequently switching between physical bodies is a significant burden and can even cause severe damage to the soul. However, the Twelve Demon Generals were demonic entities. To them, soul-snatching was as routine as a daily meal. To them, a physical body was merely a garment—something to be worn when one felt like it and discarded when one did not. This was a racial trait, something outsiders could never hope to emulate.
Out of consideration for the fact that Feng Tian was the personal disciple of their master, the group of Demon Generals not only returned the bodies they had occupied but also returned the physical forms they had collected previously in the Land of Extinction.
Chapter 219