Show Me Your Stats! - Chapter 174

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!

I reincarnated into a fantasy world. Since I somehow got born again, I resolved myself to live diligently once more. But, putting that aside, my entire village burning up and disappearing when I’m 8-year old f*cking crossed the line. F*cking shit-f*cking crossed the line!

He Lang died by his own hands for the sake of his imperial younger brother’s ambition, whom he loved. He was offered to be reborn in exchange for giving up his past romantic feelings. Reborn without the burden of his romantic feelings, he brings with him a manual to new worlds. He wholeheartedly followed the instructions of the manual to complete the tasks, not knowing that the originally slag gong was blackening…
He pleaded to his affectionate Emperor brother to release him, he pleaded to the paranoid prisoner next door, but until the end he remained baffled.
In the end, he discovered that the full name of the manual was – “Slag Shou Cultivating Manual”
Σ (っ ° ° °;) っ!

- Description from Novelupdates

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.