Counterattack System appeared when I'm already At The Mahayana Realm - Chapter 713 - 712: You If You’ve Got The Guts.....

When he did not know her true identity, he treated her very badly, he disliked her too much, she was not elegant enough, she was in the way...Only later did he realize that the woman was his legal wife! He repented, tried to recover her feelings, but she was determined to divorce him.

Noan transmigrated to a world that blends advanced technology and magic, with countless gates leading to other strange worlds.In that world, he took over the body of a young man of the same name who had just died.He realised that in this world, he was one of the 0.1% of the population who had the ability to become a landlord and had the right to go to mysterious lands to build territories.However, he was only a Rank F lord, the lowest and weakest rank in the landlord rankings.Besides, his family was like blood-sucking demons. Not only did he wear out his labour, but his younger brother was also jealous of him becoming a landlord, so he hired thugs to beat him to death.Fortunately, the 'old Noan' died, giving the 'new Noan' a body to live again.This Noan was not a coward; he was not weak like the 'old Noan'.And of course, the goddess of luck smiled upon him. Although he is only a Rank F Landlord, who can only summon useless Skeletons, he possesses the only Rank SSS talent in the world - Almighty Fusion.He can fuse ordinary skeletons and transform them into the King of the Undead, the lord of hell.He can help a weak succubus become the almighty fallen angel.He can turn a small lizard into the King of Dragons, the nightmare of all creatures.Besides, Noan also begins to lift the curtain that has hidden the truth about the new lands.

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

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!