Undead - Chapter 54

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

Back in 1991, in the face of this golden age, Chen Jianghai swears that he will only live in three words in this life: Lin Wanqiu! The story of a reborn person who built an electrical empire and reached the pinnacle of his life!

- Description from novelbuddy

There lived an extremely miserable man- he suffered from a terminal illness. But one fine day, when he left his miserable body, a certain entity grants him another chance- another life along with few gifts to help him in his journey.The man is transmigrated into the body of a young man into an ancient society. Watch how the man lives his new life and conquers the world.[This book will contain R18 scenes but do not expect it to be the theme of the book. It will be mostly based on strategies and expansion of empire. A small advancement in the technology can also be expected.]

800 years ago, 3000 dimensional gates opened across the entire world. In that moment, it was as if 3000 different colored eyes opened across the world as hordes of monsters swarmed out of these gates like tears.

Some could destroy city walls with one strike; They had bodies the size of a giant and fed on humans

Some latched onto humans, absorbing their bodies’ nutrients and enslaving humans

Some infiltrated the humans’ cities, disguising themselves as normal human beings while feeding upon human blood to sustain themselves.

In a night, the Human race fell to the bottom of the food chain.

The world had turned into a paradise for monsters…

- Description from Novelupdates