My engagement to a strange duke was unexpected

Summary

"Entertain me, okay?" A dangerous contract marriage fantasy between a mob lady who wants to avoid death and a mysterious duke who controls the country with a secret organization! Includes a newly drawn manga and a newly written short story by original author Sengoku Kanon! Lydia, the daughter of an earl, is reincarnated into a romance novel she read in her previous life. In order to change her fate of being killed by her fiancé, she asks a secret society to destroy him. She begins bargaining with the head duke, Liage, who appears as her negotiator... but for some reason, she is betrothed to him in exchange for fulfilling her contract!? Despite the disguise being based on a shared interest, a ruthless strategist masquerading as a classic hero has a mysterious obsession with her...? A dangerous contract marriage fantasy between a mob lady who wants to avoid death and a mysterious duke who controls the country with a secret organization!