Maybe a Fake Gintama - Chapter 3: Kawaki, Gintoki, Takasugi and Katsura

A rookie clerk asked his senior curiously: I heard our President is already married?

The countries of Mephius and Garbera have been waging a war for ten years and are trying to put an end to this long fight through a political marriage between the two royal families. Orba, who was driven from his home because of the war and was forced to become a gladiator, looks exactly like the crown prince of Mephius, and it has been decided he will be substituting him during the wedding ceremony. On the other hand, Vileena, the princess of Garbera, has secretly decided to ensnare the crown prince for her own country’s interests.

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

- Description from Novelupdates

Lu Xiaoran has traveled to a fantasy world and received a system, but the useless system has not been activated for a long time. Lu Xiaoran, who had no choice, could only cultivate in a low-key manner and grow steadily. However, after Lu Xiaoran had become the strongest existence in the entire sect, the dog system suddenly activated.