Ankoku Kishi Monogatari ~Yuusha wo Taosu Tameni Maou ni Shoukansaremashita~ - Chapter 137.1: The Great Sage

There was nothing left to lose in his life.He had lived as a hero. He had started at the bottom and worked his way up to the top, at the end he become the best, yet he had always been betrayed by those he had tried to protect.Humanity did not deserve his protection.When everything went out and he could no longer even hope to beg for his life, he could do nothing but look up at the blood-red sky among the corpses of demons and angels.He wished for one more chance, just one more chance.And when that chance was given to him, he swore that he would change everything. He would no longer be a hero to save people, but an anti-hero to save the world.Sacrificing hundreds of people to save an elf, poisoning hundreds of people to save a group of half-demons.He didn't care about any of that anymore, he would protect those he cared about and send everything else to hell.Not even the gods or goddesses could stop him.

Kyo Mazuru traveled to the world of Bleach and landed in the forest of Menos Grande at the beginning.Picking up a asauchi left over from Shinigami's death, and starting with a sword, he spent hundred years in the forest of Menos Grande to survive, slashing countless hollows, and his slashing skills reached the peak, until one day, he met a man who claimed to be Mr. Aizen Sōsuke!Mr. Aizen couldn't bear him to live alone in Hueco Mundo, so he invited him out of there and brought him to Soul Society!After that, Kyo Mazuru's Shinigami career began!

A child was born unable to cultivate Inner Strength. In order to gain his father's attention and regard, he resolutely chose the painful and difficult path of cultivating Outer Strength. As spring gave way to autumn, time flew by, and the child grew up... he became a young man. What truly changed his destiny was a mysterious Crystal Stone formed from a meteor—the Meteor Tear. This Meteor Tear, unbeknownst to the young man, merged into his body, and like a caterpillar transforming into a butterfly, the young man metamorphosed... And with that transformation, everything changed. And his father finally came to realize the astonishing strength of the son he had never truly invested his Heart Power in...

Taking place within a world of Measurements―superpowers owned from birth, with most being absolute trash.A world involving numerous secret organisations looking to take advantage of those rare and remarkable few possessing exceptional powers.When there exists Forbidden Knowledge better left unknown.When the discovery of said knowledge results in the inevitable; a world-ending catastrophe.‘Ignorance is bliss.’Fighting against the unrelenting persistence of the one who knows all.Before the tragic fate of the world repeats itself once more.―He must be stopped.