If Wyatt Barnes was just an ordinary practitioner entering the Void Realm, he wouldn't necessarily think this deeply.
His ability to theorize so much, with well-grounded speculation, is solely due to the fusion of the recurring Martial Emperor's memories from two lifetimes in his mind.
Moreover, he had twice encountered powerful souls attempting to destroy his own and seize his body.
So, nobody understood spiritual possession better than Wyatt Barnes.
"According to the recurring Martial Emperor's memory, if a soul is powerful enough, it can directly destroy another's soul and occupy their body, effectively replacing them."
"However, if a soul has suffered a significant blow and is only left to be a trace of what it was before, it would struggle to destroy another soul and seize their body."
"Nevertheless, though it could not take full control of another's body, temporary possession would still be possible..."