Extra's Strategy: Cultivate Protagonists, Become Invincible - Chapter 184: A Familiar Face

Doomsday comes, and human beings enter the heavenly world.
Ten years later, Yang Chen, who was betrayed tragically, returned strongly with the Tianyu bug. In this life, he vowed to make the betrayal pay the price. He has a powerful bug bonus, just like an open hang. Frightened to hear…

- Description from novelbuddy

There was a Senior Brother and a Junior Sister. One of them was transmigrated to this world and had cheats while the other was the reincarnation of a Great Emperor.

After living a mundane life for seventy years, an ordinary man named Ethan dies.Only to awaken as Caelan Aetherisin,in a world beyond his wildest imagination. Reborn as a member of a prestigious vampire royal family, he finds himself entangled in the complex power dynamics of the vampire aristocracy. With five ancient vampire houses ruling the night, tensions brew beneath the surface—old rivalries, political machinations, and deep secrets threaten to tear them apart. Yet, as they face a looming, sinister force that threatens to annihilate their kind, alliances must be formed, and the balance of power will shift in unexpected ways.As the main character navigates his newfound immortality, he must master his powers, understand his role in this dangerous world, and deal with his growing harem—each member more mysterious and powerful than the last. But with desire comes darkness, and he will soon uncover disturbing truths about his family and the world of vampires.Warning: This story contains explicit adult themes, including violence, gore, and disturbing content (incest, and more). Reader discretion is advised.

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.