Zeref X Karin - The Scandal of Sorciere

Sorciere is a fairly well-known kingdom, next to the Dukedom of Vildania, Fiore, and Korthos. The crown princess of Sorciere, Karin, is the most powerful mage in the world. Karin's heart's desire is to be loved by Zeref, the Dark Mage. Her brother, Gray, assists her in her desires by stealing the remnants of the Eclipse Gate and Lucy and Yukino's keys. Using the keys, Karin goes into the past to kill Mavis Vermillion, the first master of Fairy Tail and the one who bore a child to Zeref. However, when she encounters the master, she cannot kill her because otherwise, Gray's home would be destroyed. She lets Mavis go but kills the child and erases the memories of Mavis from a pretending-to-sleep Zeref, and returns to the present. During the present, however, her father, King Jaiden, arranges her to marry with her best friend's brother, Crown Prince Hibiki Shirogane of Korthos. The rest is a scandalous tale of loyalty and love.