City of Sin (Yanyu Jiangnan) - Vol 9 Chapter 81

A chance to change, to challenge destiny, making dreams a reality, and live a legend! A regular man gains a system that allows him to turn into a fish!

- Description from Novelupdates

A mysterious teenager who had lost his past, awakened in Tianlong Continent. Mistaken as the Ye family’s Son, he used this identity to observe this chaotic world and to search for his past self, but only to find an inevitable and terrible fate, therefore he indignantly laughed at his destiny, and revealed his prowess to rule the lands under the heavens.

The formless ancient world was infested with despicable demons. They hunted and feasted on mankind, keeping the human civilization constantly in a weak and suppressed state.

“The simplification of the extreme mountain breathing method… the simplification is successful… the extreme mountain breathing method → ​​breathing!”

Chen Fei took a deep breath.

“Extreme mountain breathing method +1 experience.”

“…”

- Description from novelbuddy