Rip!
The sound of flesh being torn asunder echoed, and two massive flesh mounds on Muria's back kept bulging until at last, they burst open, and a pair of bloodstained bone wings unfolded behind him.
After the bone wings emerged, sanguine muscles began to grow and spread across them at a visible rate to the naked eye, followed by the appearance of membranous webs between the spikes. Eventually, a pair of iconic Demonic Wings took form on Muria's back.
But the transformation did not stop there, the exoskeleton that originally grew only around his joints became thicker and more robust, and began to spread.
The exoskeleton, matching the color of Muria's skin, crept over his body until it formed a suit of bone armor that enshrouded him, changes not brought about by his fusion with the Heart of Balrog.