Monarch of Time - Chapter 38 - 38 Gathering in the arena

When an S-class elite assassin-raised captain of a special ops suicide squad comes home from a high-stakes Africa mission, he finds himself offered something that could potentially set him up for life- a curious assignment that he could use to finally exit his days of war and slaughter.

A wonder falling down from heaven! A boy possessed by strange blood! Gods tremble! Demons flee! A boy from the land of Dong Zhou. A pink skull as his sworn friend until death. A story of a determined warrior struggling for power. A legend that shakes the galaxy and disturbs the worlds of god, demon and man.

- Description from Novelupdates

Three years ago, the animals and plants on Earth underwent crazy and unexplainable changes that included transformations, reversions, and the addition of otherworldly species. And it was the start of a brand-new type of profession in the new generation of humanity – Monster Trainers, people who specialized in taming monsters.