Tidal Cage

"A century later, Earth's ecosystem collapses due to tidal anomalies, causing sea levels to rise relentlessly and continents to be swallowed by the ocean. The Octari, an octopus-like species endowed with unique abilities, quickly rise to dominance, pushing human civilization to the brink of extinction. The surviving humans retreat to the last remaining mountainous landmass, clinging to existence behind defensive barriers. In the Octari-controlled territories, humans are reduced to managed resources—every aspect of life, from survival and social ranking to marriage and reproduction, is strictly controlled by the Octari. To overcome their own genetic flaws, the Octari begin seeking out humans with superior genes, fusing with them to create a new, more powerful race. Ava is the most genetically perfect human woman in a hundred years and a top operative for the Human Resistance Front. To uncover the secrets of Earth's core, she deliberately allows herself to be captured and taken to the Deep-Sea Palace, where she becomes the genetic fusion subject of King Kassian. While navigating the treacherous court of the Octari ruler, Ava conceals her true identity, striving to steal the truth that could determine humanity’s fate, all while working with her team to fight for the return of a home for humankind."