Monster Girl Menagerie - Celestial Archive - Chapter 18 - Synchronization

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 wake of the first wave of shadow creatures, the world was plunged into ruin, a desolate yet enchanted wasteland. Humanity, driven underground, clung to survival while desperately plotting to reclaim their shattered world.But from the abyss of darkness, something miraculous stirred—a mysterious tree, shimmering with ancient power, appeared overnight. It chose only the strongest of heart, those with unbreakable will, gifting them extraordinary abilities. With these powers, humanity rose from the depths, waging war against the shadows.Yet beneath the surface of their heroic deeds lay a hidden rot. Corruption seeped into their ranks, and arrogance clouded their judgment. As their powers grew, so did the whispers of betrayal. The true battle may not be against the creatures lurking in the shadows—but against the darkness festering within their own hearts.A question lingers: When heroes fall, who will rise to take their place?

It has been more than ten years since he was transported to another world. The protagonist Deris Fahrenheit, who has became a magician with special circumstances, was freely enjoying his life in this world. However, a girl appeared before him and asked him to make her his disciple. That girl seems to be a transported person――

It’s a story of him who becomes the girl’s teacher and trains her to achieve her revenge (?) in otherworld.