Godly Replication System - Chapter 44

In a world ruled by strength and chaos, a soul from modern Earth awakens in the frail body of a seven-year-old Sakazuki. Orphaned by pirates and left with nothing but a burning hatred, he refuses to remain weak. With knowledge from his past life and the power of the Magma Magma Fruit, he begins his ruthless ascent through the ranks of the Marines.But justice is not so simple. Corruption festers within the very institution meant to uphold order, and the line between protector and tyrant blurs with every battle. Undeterred, Sakazuki will forge his own path—one paved with fire and blood.From a vengeful child to the most feared force in the Marines, witness the rise of a man who will set the seas ablaze and redefine what it means to bring order to a chaotic world.

In her previous life, she was a highly respected Heavenly Empress, but on the eve of her wedding, she was betrayed and died by self-immolation!

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

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates