You Took My Eyes, I Took Back My Love

Real mermaid princess Serena is disfavored over fake sister Lira, who her lover war god Valen truly loves. Valen cuts out her eyes and kills their child to protect Lira, leaving her dying on the seabed. Heartbroken, Serena marries the cruel sea god in Lira's place; when Valen learns she saved him and begs forgiveness, she rejects him entirely.