Maybe a Fake Gintama - Chapter 601: One Little Stroke Turns "Pain" into "Happiness"!

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?”

Civilization is destroyed and records lost. Only Dudian survives in a cryogenic sleep. Three hundred years later, Dudian wakes up and must become Dean to survive. Who can he trust in this world overrun by monsters without and within?

- Description from Novelupdates

Three years ago, to defeat the Demon God who was trying to destroy this world, thirteen Braves were summoned from another world. Each of them had varied ages and gender. Each of them was bestowed with cheat like powers not normal in this world.

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.