MTL - Tempest of the Battlefield - ~ 599 one-way door

Our protagonist Caam is a man from Earth that was reincarnated into this world as a demon. In order to survive, he spared no effort in avoiding the sparks of battle and without noticing it, he became strong himself.

Betrayed by the kingdom he bled for. Executed by the brother he once protected. Daemon died a war hero—branded a monster.But death isn’t the end. Not for him.Reborn on the day of his cursed birth, under the same blood-drenched eclipse, Daemon remembers everything: the lies, the poison, the crown soaked in his mother’s blood. This time, he won’t beg. He won’t protect.He’ll burn the empire from the inside out.His twin brother Gabriel—the golden child, the “righteous” king—stole everything. So Daemon will take it all back, piece by piece.The nobles who cheered at his execution? Dead.The soldiers who held him down? Ash.The kingdom that worshipped a fraud? Buried under screams.This isn’t about justice. This is about revenge, and Daemon’s not stopping until his brother’s skin hangs from the palace gates.The empire made a monster.Now it gets to meet him.

The ending of fairy tales is usually a happy ending of the hero and heroine. As for the supporting characters, who will care about their happiness? Having such a bad thought one day, they suddenly turn dark. They want to revolt, and they don’t want to be the main couple’s stepping stone for their ‘True love’ again. Oh my god! What’s about the plot? What kind of story will it play out with a character like this? Can it still run smoothly? The hero and the heroine are going to be crippled by the supporting character!!!!! Well, there’s actually a project to save the plot from it. By nipping the bud of all evil thoughts from them, and let the hero and heroine live together in happiness. The named of this project is ‘To save the supporting character’. All executors must dutifully do their work, and as for the mean to achieve it? Oh! That’s not worth mentioning~

No matter whether it is a white cat or black cat, if that cat can catch a mouse then it is a good cat.

- Description from Novelupdates

Yu Linglong is the shu (born of a concubine) daughter in a general’s family. Since her mother was only a tribute dancer, her position is the lowest of the low. She used to live with her mother outside the father’s residence, and they only received some monthly money from him. He didn’t bother seeing them. But when her mother dies, she moves into the general’s residence.