The SSS Ranked Demon King Goes to the Hero Academy - Chapter 47: Literary Debate.

A human from Earth is thrust into the [Hunter x Hunter] world, becoming the Zoldyck family’s defiant, red-eyed prodigy. They call me a genius and the rightful heir, but I say that’s Killua’s burden to bear.Armed with crimson eyes, and a subtle yet powerful system, I’ll rewrite destiny, upend the world, and embrace the chaos with a wicked grin.

The eldest son of the assassin aristocrat Tuatha Dé.

The skill, experience, knowledge of the previous life, magic, all of which grows his power as an assassin.

Excellent assassins pass through. He was usually admired as the ideal lord, and behind it wielded a blade as an assassin aristocrat.

For the large sum of money to help her husband, she chose to be a surrogate mother covertly. Her sweetheart was out of trouble, but she became the woman of loose morals in his eyes. Misunderstanding, disappointment and sadness forced her to divorce the man she loved from the childhood.

When she was determined to start new life, another man burst into her life. “You are my baby’s mommy and you are my wife!” A big surprise hit her that her baby’s Daddy, the man she surrogated for, fell in love with her at his first sight.

His deep love convinced her to believe the affection of love again. Unexpectedly, her ex-husband returned to beg her recombination. One was her childhood sweetheart, and the other was the man who loved her and gave her hope for a new life……Facing the two men, what is her choice?
 

- Description from Novelupdates

As a man who had lived for 20 something years and had always considered himself as a straight man, he woke up one day and found himself possessed by a stupid and cute system. Moreover, it was a gong-shou cultivating system?! Let’s see how a shou with raised hackles evolves into a (pseudo)queen shou, incidentally with a story of a hidden loyal dog gong.

- Description from Novelupdates