The Assassin's Enemy Lover - Chapter 599 - "Blue is your colour babes,"

High school student Misumi Makoto is called into a fantasy world by the god Tsukuyomi, in order to be a hero. However, the Goddess ruling the world isn’t as thrilled to have him there, and kicks him to the edge of the world. Tsukuyomi declares that Makoto is free to find his own way after Makoto is abandoned by the other Goddess.

500 years ago, Chen Xi was devoured by a crack in the void and was transported into a cultivation world.

500 years later, he returned back to Earth after enduring through several hardships and discovered that only 5 years had gone by.

…

In the courtyard, beauty at the side, a candle flame wavering.

A gush of clear wind, half a full moon, the peach tree remains unchanging.

…

Wait, whose kid is this?! Why is she calling me papa? Gazing at the little girl in front of him with skin as pale as jade, Chen Xi froze.

…

　
Returning home from cultivation, starting as a stay-at-home dad.

In this life, not fighting to be a king nor claiming to be a tyrant, only praying to peacefully be a wife-pampering mad devil and a child-protecting daddy!

- Description from Novelupdates

In the eyes of outsiders, Hyuga Yuuto is a genius in the traditional sense of the Hyuga family:

Tough, strong, gentle, and calm, he is a partner worth relying on at all times.

However, no one knows, in countless silent nights.

The young genius of the separation family stroked the caged bird engraved on his head and fell asleep with the sharp needle in his mouth, fearing that in his sleep he would reveal the madness and anger deep in his heart——

“What Uchiha Itachi can do, I, Hinata Yuuto, can’t dare to do?”

- Description from novelbuddy

Lady Bertia, who’s become my fiancée, is a bit odd. On our first meeting, she proclaimed herself a villainess noble girl who’s been reincarnated and said that she’s working hard every day to become a splendid flower of evil that’s elegantly put in her place.

I don’t get it.

But she entertains me because I don’t understand.

That’s why I think I’ll observe her for a while.

This is a story of a crown prince who’s so talented and handsome that he’s grown bored of his easy-mode life. A story of this prince observing a self-proclaimed villainess noble girl (who seems perfect at first but is a bit off) who’s become his fiancée as she snatches flags and breaks them into pieces.