The Abyss Lord's Mermaid

Mermaid princess Thea severs her own tail so she can journey onto land in search of her sister Lillian, who has been taken captive. Imprisoned in a water cell, she forms a perilous blood oath with Nemesis, the sealed ruler of the Abyss. Together they confront the merciless human king Sauron, who torments sea folk to forge deadly mechanical arms. Thea begins to unleash her full siren power, and the cost of that awakening is steep.