One Piece: I'm Destined to Be the Son-in-Law King! - Chapter 6: Jealousy Makes Me Ugly

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

An ancient proverb from the Homo sapiens era once stated, “Light and darkness can never be united because they are natural enemies arranged since the creation of the universe.”The statement seems plausible, yet it may contain inaccuracies...——————————————Leon Kruger, a 22-year-old man counted among the three of humanity's heroes, is dispatched by the Holy Empire of Mankind to invade the territory of the Demon Empire—an enduring adversary of humanity for over 7000 years.Wielding the Great Holy Sword Zenith and commanding a legion of thousands of holy troops, he leads the raid on the Desert of Chaos, facing the elite armies of the Demon Race with unwavering valor.Even, he engaged in direct combat against the Demon Emperor, who was actively leading the war on behalf of the Demon Race!Unfortunately, he never foresaw that his offensive was a cunning scheme orchestrated by the Emperor of the Holy Empire.The emperor aimed to eliminate Leon, perceiving him as a threat to his position as the ruler.Furthermore, unbeknownst to him, he had been poisoned before setting out for war, leading to a catastrophic defeat at the hands of the Demon Emperor and resulting in his capture as a prisoner of the Demon Emperor.Envisaging torment at the hands of the notorious Demon Emperor after his capture, he was surprised to find that this foreseen ordeal did not come to pass!The Demon Emperor, unveiled as a remarkably beautiful woman, unexpectedly and without apparent cause, asked him to be responsible for abandoning their triplet daughters?!“Nani! Since when did I have triplet daughters with you, smelly demon woman?!”Not only that, Leon gradually realized that an increasing number of women were approaching him to claim the love debts he had unwittingly accumulated in his youth.“Wait! Hold on! Please be gentle! Both my kidneys are nearly tapped out!”

Liu Duo was a young girl whose grandmother sold her to four brothers with the intent to be a bride. Unwilling, she ran away the following night, only to fall unconscious while trying to get away. Unexpectedly, however, she was reborn with the spirit of a 25 year old woman, also named Liu Duo.

- Description from Novelupdates

Tian Han was a young boy who admired immortals. His dream had always been to become like them—flying on swords, using spells. But he was just an ordinary village boy, and he didn't have much of a chance for that. So, he always read books about immortals, and his admiration for them grew more and more every day. One day, he heard that he had a chance to become an immortal.“You can become immortal.”This was the sentence where his adventure began. Yes, he could become an immortal. And so, his journey started, and he found himself in the ruthless world of immortals.