My Brother's the Protagonist? Good Thing I Awakened My System! - Chapter 161 Alchemist Competition

What do you do when your brother dies because of some entitled assholes? You go undercover.My real name? Clare. But at school, I’m Clause—just another guy blending in. Disguised. Watching. Yes, a boy. No, it's not an all-boys school—I'm just deep undercover, hunting down the bastard responsible for my brother’s suicide. Nobody—and I mean nobody—messes with my precious brother and gets away with it. They better pray I never find them, because when I do? Death will be a mercy, and trust me—I don’t do mercy.And as for the egotistical Alpha and the narcissistic Vampire Prince? They can go fuck themselves. I don’t do mates, I don’t do claiming, and I sure as hell don’t do them.

Nero was an orphan boy who one day went to sleep like any other day in his apartment. However, what he did not know that the moment he slept, it would be his last day of life...Or at least that was how it should be.Nero's soul wandered between the worlds and ended up entering the body of a girl who was trapped in a human mutation laboratory. While the girl's soul was still alive, he hibernated inside her body.After so many tortures, the girl named “Zero” in the laboratory died. But, it didn't end there, when the girl died, something very strange happened, something took control of the girl's body and that same thing escaped the laboratory.It was when Nero what that was hibernating in the girl's body woke up and realized was completely naked. In addition, he realized that he turned her into a beautiful winged woman with white hair and some pink strands.

Bai Aoxue, the best mercenary in the 21st century, is accidentally sent back to the Chengxi Dynasty in Great Continent due to an explosion in her mission, and trapped in the first daughter of Prime Minister. After her rebirth, she is set up by her father to marry the 5th prince Jun Yeyan who wears a mask all day long.
In the face of bloodthirsty enemies, discord between brothers, collusion among courtiers and invasion of enemy state, can Bai and Jun resolve the crises? What will happen to their political marriage? How will the fierce battle for the throne end?
With many twists and turns, the book brings you to experience palace revolution, love and hatred thousands of years ago.

- Description from Novelupdates

Xue Xi is forced to fall in love at first sight with this dangerous man on their first meeting. With death being the only other option, she makes the first move: