Maybe a Fake Gintama - Chapter 568: When Troublesome People Carry Troublesome Things, Only Trouble Ensues

Between heaven and earth lies the greatest truth, and the manifestation of the great truth descends in the form of Gu.　　People cultivate the Qi of heaven and earth around their bodies to control Gu and exert their magical power.　　One year after his transmigration, Chen Qing finally discovered his special features on the day he contracted his first Gu. He was actually able to see through everything about the Gu...　　Therefore, he began to march toward the road to immortality step by step.

In the year 1368, at the end of July, deep crimson shall descend from the heavens.

- Description from Novelupdates

The MC entered the body of the An family eldest son, An Ziran, an arrogant 16 years old boy who weighed 78 kg (~171-172 lbs), who only knew how to eat, play and sleep. Seeing his current body, An Ziran decided his first priority was to LOSE WEIGHT!

In a world where beast masters rule by taming magical creatures and competing in thrilling tournaments, becoming the most celebrated sport, Eratz seemed destined for greatness. Surrounded by friends and family, his path was set until a shocking betrayal shattered his dreams.Fueled by the pain of his betrayal, Eratz looks up at the night sky, finding a new purpose. He vows to rise from the ashes and conquer the beast master world, determined to become the greatest and reclaim his lost honor.