Universal Lords: Building an Immortal Fairyland from Scratch - Chapter 2 - A Golden Finger?

Mark hatched out of an egg one day, reincarnated as a demon!His body was as strong as iron, instincts capable of noticing a silent fly multiple meters away. Eyesight sharp enough to see the small holes in an enemy’s clothing.Moreover, he also had a system.[Soul Devourer][Eat souls to grow stronger.][Mind-type Demonic Tricks have been derived out of your demonic bloodline!][Heart Input!][Input unsolicited thoughts in an enemy's heart and influence them!]Mark took a deep breath.How can he allow himself to live a mediocre life after being given this second chance?Now, he wanted it all!Women, wealth, power, status, and even eternal life!His ambition was set, his heart was on fire. A demon had been born.

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

- Description from Novelupdates

One day, fate played a cruel joke on Fujino. When he woke up, he found himself in the world of Detective Conan. Now, he’s a high school detective with no parents, a four-story building to his name, and a barely sustainable career solving cases.Just when he was at a loss for what to do, a Professional System suddenly activated, allowing him to acquire real detective skills—through pay-to-win mechanics.From that moment on, he ditched the usual “Conan logic” and became a true rational detective, using real investigative techniques instead of convenient anime tropes.Q: Why do you, as a detective, know so many different skills?Fujino: Well, isn’t it normal for a professional detective to actually learn professional skills?

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.