City of Sin (Yanyu Jiangnan) - Vol 9 Chapter 105

They say the greatest blessing is marrying the idol you always dreamed of.

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

The world is separated into three realms: Aegaryn, Terranis, and Abyssion.Terranis and Abyssion realms have been in disharmony as the Demon King of Abyssion aims to overthrow all the other realms. In the tackling of this and to help the humans of Terranis defend themselves from the demons,A street orphan becomes a sacrifice in a summoning ritual for an S-rank beast. But he is given a golden opportunity of a lifetime as he is transmigrated into a hyena. Guided by a mysterious system that helps him unlock his boundless potential, he evolves with each rank upgrade, a feat no one of his kind has ever known. His journey is one of transformation, both in form and spirit. Each evolution brings new powers and challenges as he is summoned into deadly wars, cruel betrayals, and battles that threaten the very balance of the realms.Along his journey, he meets a summoner whose kindness and ideals are a stark contrast to all the summoners that he had met previously. Unlike the others, she treated him differently. Gave him a name. Through her, he begins to question his path, torn between his primal instincts and the flickering remnants of his humanity.But as the Demon God stirs in the shadows, threatening to collapse the realms into chaos, he must rise to face his ultimate destiny. To protect those who matter, to shatter the chains of servitude, and to ascend to the pinnacle of power—Ash must embrace his boundless evolution and become a force unlike any the realms have ever seen.

She fought in the Battle of Changping and witnessed the killing of hundreds of thousands. She once led the Qin Iron Calvary and battled against the Six Kingdoms. She has seen a third of the land and witnessed the breaking of mountains and rivers. The sound of a grand zither and the light of a great female emperor. A prosperous world that was forged on the battlefield. Yet, these two thousand years are forgotten from history.

- Description from Novelupdates