Book 1 of the Codex System Series.
*****
In the fantasy world of Terra, people are divided into two kinds: Those who have mana and those who don’t. The registered mana users are called hunters, and the ones without the mana are called plainfolk. Lin Fang, unfortunately, has been the latter since birth. 

But his misfortune didn’t end there.

After his father’s sudden demise, his mother remarried, leaving him and his sister in the hands of his grandmother. But later, his grandmother also passed away, and his sister moved abroad, leaving him all alone at just 16.

All he had left was a struggling pet shop and his late father's unfulfilled dream of making it thrive.

Fifteen years later, Lin Fang is drowning in debt, betrayed by his unfaithful wife, and addicted to alcohol. His life has hit rock bottom. Filled with many regrets, he jumped into the river to escape this suffering.

But when he did, he neither died nor ended up in the hospital.

Instead, he found himself regressing 7 years into the past, with a mysterious Prehistoric system activated by a pendant he had carried since birth.

Now, with the power to command monsters and carrying the knowledge of the future, Lin Fang set out to redo his life, whether it is becoming the strongest tamer to control prehistoric monsters, getting his true love he had walked away from before, or becoming the richest businessman.

Chapter 161 - Raw chapter