Ihoujin, Dungeon ni Moguru - Chapter 137.2: The Neomia of Delusion Notes (Afterword, and the explanation of the setting)

Imperial soldier Suldak Helansa joined the infantry regiment of the Grand Duke Newman in Bena province, participated in the Warsaw plane war, and rescued a young man in the forest battle. This qualified young man suffered some injuries. Injured, still a mute, Suldak brought him into the barracks, and what we are telling is the story of this young man of unknown origin…

- Description from novelbuddy

Lin Jiufeng transmigrates to become the Yuhua God Dynasty’s Crown Prince but is dethroned, banished to the Cold Palace, and imprisoned there because he had released the holy maiden of their rival country.

Lin Jiufeng isn’t dejected. He has brought a sign-in system with him when he transmigrated and he would receive rewards when he signs in at different places.

Before the Cold Palace’s gates, he signs in and receives the Ultimate Heaven Slashing Sword Skill!

In the Great Council Hall, he signs in and receives the Heaven Patching Technique!

In the Empress Dowager’s palace, he signs in and receives the God of War Totem!

…

Liu Jiufeng imagines that he can quietly sign in like this until he becomes invincible. Yet who would have imagined that the Heavenly Concubine whom he secretly released would rise in rebellion and seize power after she returns to her country?

After she succeeds, her first priority is to attack the Yuhua God Dynasty to rescue Lin Jiufeng.

When Liu Jiufeng hears of this news, he’s puzzled. «Do I need you to rescue me?»

The age of darkness has arrived.

Coming from the modern era, she was sent to a strange world. The body she possessed previously belonged to a young woman whose family was thrown away by their clan. However with the “Dan Fu Zong”, the inheritance from her old world, she steps on the path of cultivation, hoping to one day become an immortal.

- Description from Novelupdates