Chrome Shelled Regios - Volume 13, Prologue

Calamity descends upon a a tranquil world in the black of night, transforming it into a death game! This a a true apocalypse, but this is not the end of humanity!

- Description from Novelupdates

[Volume 1: Dante Blackthorn]When Anastasia and her sister Marianne are captured and shipped across the seas by pirates, they become commodities to be sold in a distant land. Marianne is taken as a courtesan, while Anastasia barely escapes a terrible fate by pretending to be mute. She is forced into the lowest ring of servants at the royal palace, where she endures a life of servitude and creates beautiful artwork to mask her pain.Despite years passing, Anastasia has never forgotten her sister's promise to return to their family together. However, with her movement restricted and the guards vigilant, escape seems impossible.When Anastasia comes into contact with the Forsaken Prince, her life spirals out of control and she triggers a Crux of incredible proportions. Now battling her own inner demons while navigating the treacherous politics of the royal court, Anastasia must confront the truth about her sister's fate and make a choice that could alter the course of an entire kingdom.[Volume 2: Emily Blackthorn]Princess Emily's life takes a turbulent turn when she is rejected, leaving her heartbroken and her soul at the brink of corruption. In a desperate bid to save herself, she journeys to the West.Enter the Storm Prince, a charismatic archdemon with striking blue eyes, with a saint-like smile. Emily had hoped she'd seen the last of him, but fate has other plans. As if her soul dying isn’t enough, someone wants to steal it!Caught between the suitors and the haunting nightmares that have plagued her since childhood, Emily begins to see Raylen in a new light. The blue-eyed demon may not be the monster she once thought.

Zavier met Cosmic Consciousness after his death. He was satisfied with every system that Cosmic Consciousness exhibited, so he wanted all of them. Surprisingly, the Cosmic Consciousness obliged him.

Zavier was reborn in an isekai full of magic and alchemy. Now, he had many routes to upgrade. Interestingly, to coordinate these systems, Cosmic Consciousness gave him the gift of being able to duplicate himself. He could clone a finite number of himself to manipulate these systems.

Magus, Alchemist, Mesmer, Tamer, Hunter, Vampire, Werewolf, Dragonknight, Necromancer.....

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By the way, it wouldn't appear NTR or some bullshit harem of courtships. MC of course will have harem but not for cliches.

Athena Grant,a human,dies in a car accident and becomes Eira Liora,an elf. Transported to the barren and cursed island of Luinmir, a once-thriving land now abandoned.A year ago,their King announced that the island,Luinmir would no longer be under the empire's control. It was well known that the land was barren and poverty stricken...She was abandoned both by her Kingdom and her Father.She wakes up one day with a system.“So what if they were abandoned and deemed cursed,she would show them all the highest peak of knowledge and development. The island's core is broken...fine,she'll get it replaced but this time,the island would become hers to keep,she would make sure of that.”