My System Increases My power Every Day Without Missions and Levelling - Chapter 275: Young Lord Gray

The world is terrorized by the powerful Black Witch who has been sealed in the moon. Every ten years, the night of Hexennacht arrives and a chosen witch must battle the Black Witch in hopes of finally defeating her.

As the current decade’s Hexennacht approaches, a mysterious girl named Kagami Kagami arrives and meets Horinouchi Mitsuru, the daughter of the previous Hexennacht representative.

It takes place between Kyoukai Senjou no Horizon and the City Series, two other series by the author.

A part-time job contract. He became the cold CEO’s imitation boyfriend. He merely wanted to earn a few small bucks and live a comfortable life, but a pity, he was in constant turmoil since then. Well, life had something else for him despite his wishes.“That… beauty, will there be an increase in wages for conversion from ‘boyfriend’ to ‘husband’?”

- Description from Novelupdates

These days, could one really time-travel just by dreaming? And to become a silly princess at that. Well, marrying a domineering man wasn't too bad. His taking a concubine wasn't the end of the world either. But why was she forbidden from liking anything except him? That was just too domineering! She had to escape! Ah, but upon escaping, she realized he was a half-demon who didn't understand love... and, moreover, a half-demon who had a three-lives connection with her...

It was supposed to be a perfect deal in which both parties got what they needed. However, after the child was born, he tore up the agreement with discontent and told her, “Who said that we’d only have one child? I want twins! Twin brother and sister! You’ll continue giving birth to more children until you bore me a pair of twins!”