The Retired Young Mercenary Is Secretly a Billionaire - Chapter 3: The Letter Keeper

There is a turtle here,It's a bandit! A thief! A shameless scoundrel!Don't provoke him!~~~~~~~~~~~~~It doesn't belong to the orthodox realm of mythical creatures; it falls under the genre of Xuanhuan and Xianxia. I hope you all are aware of this.

Akira Kuromiya is just an average high schooler who gets killed by a robber. He wakes up and is now a chicken!? Even worse he becomes the familiar of a girl who's apparently the heiress of a powerful clan.

That was for a short while though, as he was abandoned and woke up to find out he, now she, is trapped in a deadly magical forest with all sorts creatures trying to kill her.

The world she finds herself is one of magic and monsters like the manga she's been reading. Akira, now Hinotori is trying to live her life as a chicken in another world!

Doomsday comes, and human beings enter the heavenly world.
Ten years later, Yang Chen, who was betrayed tragically, returned strongly with the Tianyu bug. In this life, he vowed to make the betrayal pay the price. He has a powerful bug bonus, just like an open hang. Frightened to hear…

- Description from novelbuddy

Reincarnation.A concept everyone is all too familiar with, at least once in our lives, we've all thought of being able to just let go of all our regrets and the things holding us back and just start over.This deal is made even sweeter when paired with being allowed to keep your current memories and knowledge of the future.William was one such boy who had been given this once-in-a-lifetime opportunity.Like any other modern-day person, the first thing he did after learning about his reincarnation was check if he possessed any memory that was similar to his new world.Sadly, in the end, he was left disappointed and was forced to go into his new life completely blind and unaware of all the malicious entities, world-ending threats, and divine schemes going on in the shadow.But then again, who needs knowledge of the future when you are the child of mana itself?