Internet Magic in Fairy Tail - Chapter 180 - : Magic Net’s Love Guru, Kain Hikaru

The Apocalypse is in full swing. Defiled - powerful creatures corrupted by the Great Collision - prowled the lands in search of prey. Unfortunately for them, the human race had long since retreated behind the secure walls of the Sanctuary of Everlast. During one of his regular excursions outside the Sanctuary, Alden is separated from Celeste. - his childhood friend and crush. In that moment, he came to regret never summoning the courage to confess. Somehow managing to survive thanks to some trickery, Alden awakens as a mage. Instead of receiving a normal power, he gains the ability to decay. What’s more, during his ascension, he received a vision from his future self advising him not to trust the Asterons - celestial beings who had saved his race from inescapable doom. Normally... such a revelation wouldn’t faze Alden. However, there was only one major problem with the declaration, though. Celeste was bound with an Asteron. And not just any normal Asteron... She had made a pact with one of the Divine Sovereigns.

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- Description from Novelupdates

The eldest daughter of the Li family is beautiful and sassy, ​​she took space materials to flee famine, and after going through many difficulties in war, disease and epidemic, she united with her family to regain the glory and harvested a beautiful boy.

- Description from novelbuddy

This world has Fox Fairies, River Gods, Water Monsters, Great Demons and Cultivators who seek immortality.