In one of the deepest and darkest parts of the Blue Star's ocean, there is a set of buildings made of ebony stone; dark energies are more intense in this place than anywhere else in this world as it is the biggest of Tyrion's special prisons.
There, the Naga King's special servant, the Siren Tanu, usually does experiments with Blue Star's most powerful creatures, using dark magic to try to corrupt those monsters to obey Tyrion.
But now, with no time for further experiments, she is working on the greatest spell of her entire life. Using life as fuel for a malefic dark spell, Tanu is simultaneously creating multiple portals to send the most brutal and craziest creatures from that prison over the Mermaid Kingdom.
Inside the largest room in the main building, she floats in the midair while channeling mana into a vortex of dark magic. The vortex creates black siphons that suck the vital energy of different prisoners like animals and even people to open the portals.