A Mistaken Marriage Match: Mysteries in the Imperial Harem - Chapter 71

This is a prequel to the anime movie To Aru Majutsu no Kinsho Mokuroku – Endymion no Kiseki.

Just before the completion of the Academy City space elevator “Endymion”, the main characters Kamijou Touma and Index encounter a level 0 girl named Arisa. The Magicians are after Arisa, and they attack Academy City. A female leader named Shattoaura leads a unit from Academy City against the attack. Kamijou and Index learn from Stiyl that Arisa is key to a brewing war between the sides of Magic and Science. When science and magic cross paths, the story begins with Endymion as its stage!

Escaping from the wedding she dreaded with Crown Prince, Aed Ruad, Princess Anastasia ended up becoming the captive of the Lore's most dangerous man, Prince Ileus.

Qi Condensation. Foundation Establishment. Core Formation. In the current world, only these three realms are known to be achievable. Nascent Soul is but a legend and the realms above it lost to the the long river of time. The modern era is known as Cultivation Civilization, a balance of power and civility, excess and moderation. While cultivation remains a secret practice, it has long since exposed itself to the mundane world, quietly intertwined with each facet of society. While the world appears to be at peace, what lies underneath is a conflict between human, cultivator, and demon, brewing for ages and waiting to implode. Yet in the wake of humanity’s rapid industrialization, qi—and consequently cultivation—is dying.

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