Pokemon: Farm Story - Chapter 21: A Passing Trainer?

At the end of the world, a legendary hero gave his life to save a dear friend, only to be reborn as a four-year-old orphan with 'Crab Affinity'.The apocalypse has come and gone, claiming humanity with it. All humans have had their 'Souls' stolen and claimed by monsters - vampires, demons, zombies - you name it.Reborn as Barnacles (Barns for short), the once-legendary hero claws his way back to strength under the tutelage of the gluttonous King Crab, a sentient crustacean with more vice than virtue in his shell.Follow Barns' journey as he rediscovers his power of rebirth, which when combined with a little 'crab magic' has the power to reset humans back to their original selves.It's time to take a crack at resetting the apocalypse.

He was on his way to buy some beer to celebrate his acceptance as a civil servant when he was suddenly isekai’d by truck-kun.

I’ll give you an opportunity—but not for free.Gates have opened all over Earth, unleashing hordes of monsters from other dimensions. Humanity stands on the brink of extinction, with only ten years left until the end of Earth as it is.With my awakened skills, Record and Time Rabbit’s Luggage, I’ve spent seventy-six lifetimes trudging through these grueling regressions. The repetition ends here, on this Attempt.But it’s unfair if I’m the only one suffering, right? So let’s share the burden.“Ah, don’t sweat it! I’ll give you a good opportunity. For what you’re getting, it’s a bargain, don’t you think?”

As Mingguang Sect’s esteemed Immortal Master, Yi Ning had never experienced much heartbreak and suffering. He had always expected his life to be smooth-sailing, and was only waiting to ascend before marrying his disciple with whom he shared mutual affection.

However, he had never expected that on a rainy night, his disciple brought back a childhood friend.

They were close and intimate, to the point… of sharing a bed.

Standing before the bed where they were entwined, Yi Ning’s heart was as cold as sunken ice. He had wanted to end it all cleanly and straightforwardly, yet had never expected that his disciple not only wanted his childhood friend, but wanted his Shizun too.

His disciple shattered his spiritual core and laid down a hex, throwing him into the main hall to await nightfall to consummate their relationship.

Just as he had fallen into despair and wanted to end his life, he unexpectedly discovered a strange book. The book detailed his life, and the him it described, from beginning to end, was nothing more than a tool used to satisfy his disciple’s desire to conquer, lowly and wretched as a cultivation furnace.

Yi Ning’s head spun, and his heart gave birth to a strong hatred. He dragged his wrecked body to the back of the mountain and released the Demon Venerable Yan Xuan, who he had personally sealed nine years ago.

In return for undoing the seal, Yan Xuan would aid him in escaping.

After the man heard the reason why, he leaned against the wall and smiled with a hint of mockery. Yi Ning had thought he was going to ridicule him for having deserved it, being betrayed by an ingrate who bit the hand that fed him.

Yet, what he never expected was for Yan Xuan to reach out and tug him into his embrace, and the words that left his mouth were instead:

“You fool, I’ll help you take revenge.”

After this, he killed all those who wronged him, and cradled him close to his heart.

He wants to shatter your cultivation and mangle your limbs, to turn you into a bird in a cage, free for him to humiliate.

Yet, with this lowly and dirty heart of mine, I want to pull you from the swamp and cut down the heavens for you.

- Description from Novelupdates