In the Second Generation of the Trench, He Changed To the Ruanfan Script - Chapter 23:

Jiang Pengji got something called the Court Intrigue Stream System.
System: “Your goal is to become the most prestigious woman in the kingdom (the Queen)!”
Jiang Pengji: “Okay, System. No problem!”
Years later, she met the target by becoming the most prestigious woman (the Empress).
Jiang Pengji: “Well done, no?”

- Description from Novelupdates

Ask, under the starry sky there was a beauty, her black hair like eternal night, bright eyes sparkling like stars, her powerful magic made the world tremble, her supreme beauty made all creatures submit, who was this beauty? “That’s right, it’s me, the Witch King, Dorothy!” ‍

Zaiyila thought she had suffered enough—betrayed by her own mother and sold into marriage with a wealthy, aging man. But on the night of her pre-wedding ceremony, everything takes a dark and unexpected turn. A swarm of deadly snakes descends upon the gathering, killing her groom-to-be and throwing the hall into chaos. Fear spreads as the people recognize the serpents as the servants of the enigmatic and terrifying Snake King, Everett.When Everett himself arrives—a striking, horned man of unmatched beauty and power—Zaiyila finds herself drawn to him in ways she cannot explain. Despite the fear he inspires in others, she feels an unshakable connection to him, one that transcends the realm of logic. The moment she defies the fearful kneeling of the crowd, she unknowingly seals her fate.Taken into Everett’s domain, Zaiyila is forced to confront not only the dangerous, supernatural world she’s been thrust into but also the awakening desires she cannot deny. As she unravels the truth about her past and her connection to the Snake King, she must decide—will she resist the pull of destiny, or will she embrace the darkness and passion that Everett offers?A tale of betrayal, power, and an irresistible bond, Bride of the Serpent King explores the fine line between fear and desire, fate and choice.---

An otaku with a hobby of masturbating was reincarnated as the son of a great mage.

As soon as he was born in this life, he vowed with a goal of embracing women till his death.

That said, when he became 20 years old, the Demon Lord which was sealed by his ancestors revived, and now it is his role to seal it once again.

And that demon lord is sealed in a tower dungeon that is rumored to be impossible to capture.

However, by an unexpected coincidence, he had found out that the Demon Lord is also one of him, a kindred spirit from within,

so he joined her instead and filled several traps in the tower dungeon, and thus they enjoyed a s*x spree with all the women coming over!