Brinny and the Empty Seat

The story of a possessor from a book who, for the sake of its goal, won't mind killing others.

Brinny, who's living while adapting to her stepfather, thought that story had nothing to do with her. Up until she was swept into an incident with the sickly second prince, Lucian. In the midst of the crisis, Brinny rescued Lucian by displaying her superhuman strength, and looking at the possessor "Ariadna" tied up had reassured her that everything had been resolved.

But for whatever reason, her beloved older sister and the first prince died in a carriage accident, and then even Lucian, who later became her fiancé, started to display some abnormal behavior.

The possessor wasn't executed in the past. Would "Ariadna" still be alive? In order to regain the empty seats of their lost loved ones, Brinny made a decision: To fight against the possessor.

(Source: Kakao Entertainment, translated)