They bound the Forethinker's hands and suspended him here, where there was clearly no fulcrum to hang from, yet the chains somehow held Prometheus aloft in midair. Then Bia took out a long nail and drove it forcefully into his chest.
Blood flowed down his body, eventually falling into the vortex below. When they had finished this step, the two stepped back and stood beside the God of Sun.
At that moment, an immense pressure poured onto Prometheus's slender body, causing his bones to creak and groan.
At sea, the restrictions of the present world were slightly more lenient than those on land, so the God of Sun had been using Divine Power to resist the pressure at this oceanic maelstrom, but the long nail driven into the chest of Prometheus locked away the Titan's Divine Power, forcing him to face the pressure with his own flesh.