Margrave's Bastard Son was The Emperor - Chapter 251

There was a woman. Born as an illegitimate child and raised under the strict control of the queen, her world was as small as a well.

There was a man. He was forced to marry a woman who was his brother’s political marriage partner. His world, which was infinitely wide, became smaller.

The woman’s original sin, and the man’s resentment. “I should have just died instead…”

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Ukei Kaito fought a desperate struggle in order to fulfill his role as a summoned hero. He defeated the Demon Lord and saved the very world, only to meet an end filled but with betrayal. The companions that he’d trusted throughout his journey betrayed him and killed him by sticking a blade through his chest.

JAYDEForged in the crucible of Xi Corporation’s labs, Jayde—once known only as SN1098—is a genetically engineered super soldier, her body honed to a razor's edge through decades of fighting humanity’s brutal wars. Her rebellion against her creators sparked a desperate battle for her people’s survival, only to end in betrayal and a fiery death on Crypso 3Q3U, her sacrifice shattering the corporate chains binding thousands of GESS lives. Yet death is not her end. Jayde awakens, impossibly, in the tortured body of a young girl on a strange world untouched by the technology she knew—no starships, no replicators, no blasters, only the primal pulse of magic. Bound to an ancient artifact pulsing with secrets, she must navigate a realm of powerful mages, mythical creatures, and lurking monsters, her old instincts clashing with the arcane forces now at her command. Her soul, scarred by battle and betrayal, carries a darkness that threatens to consume or redeem her as she carves a new path.RENRen, the fierce demon king, stands as the last bulwark against his race’s extinction, his heart a furnace of primal fury. To save his people and halt the malevolent Zartonesh’s invasion of the realms, he must venture to the Lower Realm, where the Devil Wars first ignited. His fate entwines with a young woman—Jayde—whose soul, steeped in shadow, stirs the ancient beast within him. Her vast, untamed power could be the key to salvation or the doom of all he fights for, her presence a spark to his fire, a bond that could forge or shatter destinies.AN EPIC JOURNEY OF MAGIC AND REDEMPTIONJayde trades her blaster for a sword, stepping alone into a universe where magic hums like a Centauri war-chant, guided only by a mysterious artifact that whispers of forgotten truths. She journeys across dimensions, learning the art of spellcraft, forging alliances with unlikely companions, and facing enemies born of myth and nightmare. As she grapples with the darkness within her soul—a remnant of her past life’s pain and betrayal—she searches for her true-mate, a bond that could anchor or unravel her. Will she master the magic of this strange world and rise as its savior, or will the shadows she carries bring ruin to all she holds dear?WARNING: This tale unfolds as a slow-burning romance, weaving love and loss through a tapestry of magic, sacrifice, and defiance, as Jayde’s legacy burns brighter than any star.