I Became a Plutocrat in World War I: Starting with Saving France - Chapter 20: Revised - The Smiling Man

Dante was an ageless warlock who had been going from one battle to another for hundreds of years.Following a chaotic encounter with an evil god, Dante unintentionally activates a contract with a demon, thrusting him into the modern world.Resolved to live a peaceful life, his intentions are halted when he finds himself in the middle of a conflict among rival mafia factions—dabbling with the ominous demonic magic that he knows best.

A good-for-nothing man married a beautiful girl but was kicked off the bed on the wedding night. Furiously, he wrote a bill of divorce and ran away.
He was schemed a car accident in which he nearly lost his life. However, it turned out to be a blessing. He swallowed the soul that passed through the outer world, thus obtained superb medical skills and martial arts.
Later on, with the silver needles and invincible martial arts, he embarked on the road of counterattacks and was committed to his great dreams.

- Description from Novelupdates

Rein Aster was just a herbalist farmer from a border village.A nobody. A background NPC in a story filled with prophecy and divine warfare.But by chance—or fate—he saves one of the 7 Demon Lords during a catastrophic war event. Instead of killing him, she falls for him.Obsessively. Violently. Eternally.And then… so do the others.Each Demon Lord tries to trap Rein as her personal lover/pet/priest/husband/god, building dungeons, illusion palaces, soul prisons—but Rein keeps escaping. Quietly. Cleverly. Never fully rejecting them—but never submitting, either.Why?Because Rein realizes something:The gods are worse than demons.The heroes are tyrants in shining armor.The world is collapsing—and he’s the only one they all listen to.So he hatches a plan:Use the Demon Lords’ love to take over the world.Pit them against the heroes. Unleash them on the gods. Make them fight for him. Make them kill for him. Then tame them all.Not as a king.Not as a savior.But as the lover they would burn the world for.__________The yanderes here are darker than what you might be used to.You have been warnedThe entire novel has a dark feel. Atleast read the first two minor arcs

Wait right there!!! You stopped?! Good. Now, read below. I know what you guys are here for, so let me make it clear from the beginning, this novel has everything you want to see, like... Milfs, Virgins, Netori, No Yuri, Act of keeping the bloodline pure, Oyakodon, Succubus, Vampires, Elves, Queens in the harem, Princesses, Gilfs, Demonesses, Angels, Goddesses, Dragons, Phoenixes, Dryads, long seggs scenes, Dual cultivation, Cultivation, System, Yandere, Overpowered MC, and many more. This was something for the more cultured people, but besides these, this novel also has... wanna guess what is it? Hmm...?! Yep, you got it! A good story, that won’t make you feel bored, if you don’t quit in the beginning that is. It has many plot twists and many new concepts that you won’t see in any other novel.