Shadow Monarch in DC - Chapter 22: Secrets of Blackwynd.

“I hate this world. I hate everyone. There's no justice for the weak,”Once happy and carefree, Reign's life took a dark turn when he was kidnapped and undergone brutal experiments.These trials broke not only his physical body but also shattered his mind.In the end, his body couldn't withstand the ordeal, and he died like a pitiful lab rat.But death wasn't the end.He woke up in a new world as a corpse, armed with the Ultimate Mutation System.A system that enabled him to mutate and gain power in exchange for his own humanity.Determined to avoid being exploited again, he sets out to become a true powerhouse.He knew that being weak would only make him a target, especially now that he was a monster.“Kill or be killed.”That was his only option.

Throughout this current life of mine, I will pay no attention to my past lives, nor will I seek future lives. I wish to live vigorously, to pay back debt of gratitude and fulfill duty to avenge, to defeat valiant heroes from all species, and to proudly laugh at all the Gods and Demons of the Six Path of Reincarnation!

- Description from Novelupdates

Xiao Rou, a girl growing up in a poor countryside family, finds that she’s actually the daughter of a wealthy couple. Her mother had mistaken another girl for her back at the hospital. Thinking she would change from an ugly duckling to a noble swan and live happily ever after with her real family, reality strikes her in the face.

There are times—far too many times—when you feel that uncontrollable urge to kill someone.For Kaya, this… this was exactly that moment.“Repeat what you just said?”She’d seen hell on the battlefield—second-in-command of a military unit, dodging bullets, dragging traitors by the collar, and coming out alive with grit under her nails.But nothing, absolutely nothing, prepared her for the sight of her spineless husband flirting with her own sister. Right in front of her.“I could never marry a barbarian like you. The one I... I like is Meera—”Blah blah. The same pitiful nonsense again.You think—what could possibly be worse than this?And then, right on cue, your idiotic sister chimes in, completely serious, “I just poisoned you.”Wow.BANG.Before anyone could even react, Meera collapsed.Dead.Her so-called husband gasped like a fish dragged out of water.“Y-you…”He dropped to his knees, staring at Kaya like he was seeing a monster rise from the dark.“You killed your sister?! How could y—?”BANG.Second bullet.Same spot.He dropped like a puppet with its strings cut.Silence....Just when Kaya thought her story had finally reached its bitter end, the universe—no, god himself—decided to throw in one last, ridiculous twist.“Wife… wife, didn’t you say you were gonna eat me? Why’d you stop?”A snake beast, ridiculously charming and glowing like some immortal fantasy, clung to her, eyes gleaming.Another voice interrupted.“Shut up! My wife wants to cuddle me now—”A sparrow beastman leapt into her arms, like that made any sense.“Hic… wife, don’t you want me anymore?”A panda-like beastman sat beside her, huge, sniffly, and wronged like a child abandoned at a festival.Sitting in the middle of all this, Kaya was absolutely dumbfounded.‘When the hell did all of this even start?’