It Seems That I've Slipped Into a Different World. Also, My Gender Has Changed. - Chapter 10: Abundant Learning, during a Castle Tour (Part 1)

Emperor Ian Veroshion, the first noble mage, was betrayed and executed. Cursed to never be reborn, he awakens a century later as the illegitimate son of a disgraced ducal line, destined to be a hostage in a barbaric land. Stripped of his magic and his throne, he must navigate a world vastly different from the one he ruled, facing political machinations and a resurgent monster threat. But the embers of his past life still burn, and Ian will not surrender his legacy. He will reclaim his name, his magic, and perhaps, even his empire.

A Deadly Secret, also translated as Requiem of Ling Sing and Secret of the Linked Cities, is a wuxia novel by Jin Yong (Louis Cha). It was first published in the magazine Southeast Asia Weekly (東南亞周刊) and the Hong Kong newspaper Ming Pao in 1963. Its original Chinese title was Su Xin Jian before Jin Yong changed it to Lian Cheng Jue. The story revolves around the adventures of the protagonist Di Yun, an ordinary young peasant, who is imprisoned after being framed. In his quest for vengeance, he accidentally acquires the Liancheng Swordplay manual (連城劍谱), an ancient artifact not only prized for the skills detailed inside, but also for containing a secret leading to a treasure.

This novel is also known as The Demons Beside Me

Chen Zhao can summon demons and see Death.

“Beelzebub, use your Gluttony ability to treat this patient’s anorexia.”

“Raymond, this old man wants to regain his manly function. You know what I mean.”

- Description from Novelupdates

Li Yuanqing transmigrated and became the crown prince of Northern Kingdom. He was sent to the borders, after his cultivation and meridans was crippled, because he refused to marry a princess and was not allowed back into the palace ever.

Just then, the Hundred-fold Sign-in System was activated!

Outside his house in the Wilderness, he signed in and received 100 Replenishment pills!

Beside the lake of the Wilderness, he signed in and received 100 Marrow Cleansing pills!

Among the warriors of Myriad City Kingdom, he signed in and received 100 Heavenly Skill manuals!

…

Li Yuanqing had thought that if he just signed in silently and received the hundred-fold reward, he would be able to watch over his younger sister until she became the ruler of the kingdom and until he became invincible.

But he had never thought that one day, the queen of Myriad City Kingdom would come to meet him!

“I am willing to use Myriad City as my dowry. Will you marry me, Your Highness?”

Li Yuanqing did not know what to do when he looked at the queen smiling beautifully before him…