Rakuin no Monshou - Volume 5, Chapter 1: The Mercenaries of Tauran

His Royal Highness the King of Han, who was afraid of the dark and ghosts and loved to cry, has always been the good baby of the princess.
Until one day, His Royal Highness the King of Han found a book in the bookstore…
Picture book?
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Search keyword: Protagonist: King of Han, Princess of Han

- Description from novelbuddy

Alexander lived—and died—as a wretched, poor virgin, meeting his end as he laid in the hands of his own mother.Stricken by a strange illness, his final vow was a desperate plea: If I’m ever reborn, I’ll attack all the ladies. I'll give my canal desires more attention!Miraculously, fate answers.Reborn into a world eerily similar to his last, Alexander awakens as a Guardian Candidate—a chosen warrior destined to endure trials and serve the gods.But he has no interest in destiny. Armed with divine skills and a frustratingly incompetent and seductive system, he rejects his ordained path, determined to seize this second life for one purpose: conquering women.Now, as a self-aware, unapologetic pervert, Alexander embarks on a relentless quest to charm, seduce, and claim every beautiful woman he encounters.Will his insatiable appetite lead him to the harem of his dreams, or will his reckless pursuit bring another premature end?Join Alexander in this wild, uninhibited adventure—where desire defies duty, and pleasure reigns supreme!

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.

My name is Chen Mo, a gaming nerd.Recently, I've been obsessed with a single-player game called “Absolute Immortal” and have defeated the final boss, [Lady Yu], over a hundred times using cheats.Then, I transmigrated.I became Lady Yu's lackey.On my first day at work, why does it feel like Her Majesty is looking at me strangely...?...My name is Yu Youhan, Imperial Consort of the Yuan Dynasty, with immense cultivation power, dominating the nine provinces.I recently had a 'dream'.In the dream, I was wantonly tormented by a man, utterly powerless.I initially thought it was a mistake in my cultivation, thus giving rise to a heart demon, until that 'inner demon' appeared right in front of me......Within the high walls of the deep palace.'There are many ways to conquer a heart demon, it doesn't necessarily have to be through force...''Your Majesty, I, I admit defeat!''Who allowed you to admit defeat? Dare to defy this palace, and you'll be punished for another hour!''...'