I Can Peek Inside Every Place And Even Record It - Chapter 19 Journey Part 1

The unparalleled Demon King Ye Xuan, who was able to heal the death or the living alike and holder of the medicine Holy Scripture, was betrayed and killed by his fellow Demon Kings. But he reincarnated into the body of Ye Xuan, the prodigal son of the Ye family and vowed to himself that he would return to his peak and take back everything that belonged to him!

- Description from Novelupdates

Dimensional Rifts permeate throughout the Chaotic Universe, bringing with them immense dangers… as well as innumerable treasures.

In a small Realm, a destitute boy awakens the Idle Gaming System.

Countless Dimensional Rifts later, he lazily raises his head to realize… he is invincible!

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

After transmigrating into the Marvel-DC multiverse, he, once an ordinary person, has now become a world-renowned mercenary and assassin.Things have changed. Should he become a righteous hero, or continue his dark profession?“Don't use such shallow concepts like good and evil to judge me. I only do what I want.”Suddenly, the protagonist appeared behind the author of this synopsis, punched him, and sent him flying.“The truth is simple. I am the death knell that rings in everyone's ears!”