MTL - There is Room For a Beautiful Daughter-in-law In the Rebirth Era - Chapter 40 you are blackmailing

Cho Ryu Hyang was good at math from a young age. When he enrolled into the The Theoretical Maths and Martial Arts School, the teacher, Jo Gi Chun, recognized Cho Ryu Hyang’s talent immediately and took him in.

Reborn into the Marvel world and become the son of the boss Jin Bing, what about the prince of the underground forces?

Don’t panic, the Black Shadow Corps provides the most loyal subordinates!

Twelve spells give you extraordinary power!

The eight demons will let you master the supernatural powers of overturning rivers and seas!

If you want to challenge, line up and come one by one!

- Description from novelbuddy

Kurokawa Risa is an ordinary office worker, who has practiced lots of cooking while living alone. One day, she wakes up in another world, with a concerned little spirit hovering over her! She has apparently been transported to a magical, spirit-filled realm by the will of the goddess, and there is no known way for her to go back. She is taken in by a wealthy couple, and they and her new spirit helper treat her with nothing but kindness. There is one problem, however–the food in this magical world is gross! Risa insists on helping the household cooking staff prepare a traditional meal from her world, and it is a big hit with her hosts. Soon Risa knows what she should do in this new world; she should open a cafe and treat everyone to delicious food!

I finally managed to kill the demon lord.