The Tidal Saintess and Her Three Champions

Mermaid princess Aria is betrayed by her fiancé Aiden and stepsister Meryn, stripped of her bloodline by King Oren, and thrown into the abyss—but awakens tidal power and bonds with the abyss entity Silas. To avenge her mother and expose her father's plot, she allies with human King Kaelen, her half-brother Brett, and three guardians. She overthrows the tyrant, gives birth to a crossbreed daughter Angela, and ends centuries of war with a golden tail, building peace on ruins.