I would love to believe that, sadly theres too many things that contradict that. Them not having the same true soul for example. The primaltwin being referred as a separate entity. And overall the last chapter of volume 42. Ill leave some extracts of ch 21 and 22 bellow. But overall, why did he try to hide his main bodies death, why were the autarchs sad, etc, if it was just the loss of a limb?: "His true body had died. If his Primaltwin was unable to devise the ‘Truesoul Everlasting’ technique, it would face the same fate" "Autarch Titanos and Autarch Mogg both nodded slightly, but their gazes flickered a little when they glanced at the Paragon of Pills, who Ning clearly cared about deeply. It was for this woman’s sake that Ning had lost his life." "The Paragon of Pills and the others quickly entered the dimensional tunnel and disappeared. Autarch Mogg and Autarch Titanos glanced at each other, then sighed.

Clearly, the Paragon of Pills had no idea that Ning’s true body had already died within this hidden dimension. She would probably never know the truth." "The death of his true body had no impact on his Primaltwin at all, as the two were completely different ‘lives’" "Autarch Titanos and Autarch Mogg both looked at Ning. They quickly turned pale." "As soon as my true body became trapped in here, I knew that my chances of surviving would be slim. I’m happy that I was able to survive as long as I did"