Dominating Sword Immortal - Chapter 876 - Ye Chen’s Guess

A novel revolving around being transported to another world with an op system. The mc spends his day chasing skirts and doing missions to level up. A standard journey to the top with lots of girls from various animes and games with a twist of that gaming feel (hunting mobs, doing missions).

- Description from novelupdates

Karl Adelheit, a self-proclaimed ordinary student returning from military service.

And a nobleman who enlisted as a soldier and received Medals of Honor.

She was once an heiress, but later her family went bankrupt, and her fiancé betrayed her. Besides, she had to bear the expensive medical expenses of her brother. Therefore, to regain everything, she decidedly married her ex's cousin in a deal. Initially, he was very aloof and didn't care about women at all, but he gradually fell in love with her, protecting her and supporting her...

Entering Tokyo in the bubble era, in this strange era, the only familiar ones are Matsuda Seiko, Nakamori Akina, Kudo Shizuka…

- Description from novelbuddy