Die Melusine

Read manhwa Die Melusine / My serenade, my Kieron. During one of his conquests, the heartless Archduke Kieron discovers Melusine, a mermaid in captivity. Their bond deepens, but according to legend, mermaids must kill their lovers to return to the sea. Melusine cannot bear to harm Kieron and leaves instead. What cruel fate awaits the lovers?