After the skin bag enveloped 'Negary', he took on almost the same appearance as Michael, except there were now a few burn marks on his neck.
By taking on this skin bag, 'Negary' easily inserted himself into the process of this magic ritual.
In the first place, magic rituals that changed one's species into another in order to obtain a second life were full of dangers, any mistakes could easily result in irreversibly terrible consequences.
At this point, 'Negary' had been able to thoroughly analyze this magic ritual. It used the caster's brain, innards, muscles, and bones as the four pivots of the ritual, which would first undergo species conversion into maggots, leaving only the skin in human appearance to act as the center of the ritual.