Whether it was the Monster Soul of Qin Miesheng that appeared for the first time to perish with Su Changkong, the Monster Soul of the previous Demon Monster clone, or the Monster Soul of the 'main body' that was chopped, all were one of the many Monster Souls bred from the Demon Nest.
Most Monster Souls were still very weak and couldn't leave the Demon Nest to move freely. Once, Qin Miesheng had sacrificed a Monster Soul to perish with Su Changkong. It took years for the Demon Nest to nurture another Monster Soul to a state where it could act independently outside again.
"These Monster Souls... are all Qin Miesheng, or rather, Qin Miesheng himself is a split soul of the Demon Nest, a consciousness. The Demon Nest itself is the real 'Demon Monster'!"
Seeing those fierce faces, Su Changkong also had an epiphany.